Since my last Windows Update (not sure that's the cause), I'm having a hell to regain access to my Terratec DVB-Tstick with ther Elonics E4000 tuner. I've modified librtlsrc.c to include some more traces and relinked rtl_test with it. All I'm getting is LIBUSB_ERROR_PIPE trying to read/write the I2C-bus: Osmocom-SDR\src\rtl_test.exe Found 1 device(s): 0: Terratec T Stick PLUS Using device 0: Terratec T Stick PLUS librtlsdr.c(392): I2C addr C8: got 00, rd_len: -9, wr_len: -9 librtlsdr.c(394): Read error: LIBUSB_ERROR_PIPE, Pipe error librtlsdr.c(396): Write error: LIBUSB_ERROR_PIPE, Pipe error librtlsdr.c(392): I2C addr C6: got 00, rd_len: -9, wr_len: -9 ... No supported tuner found Enabled direct sampling mode, input 1 Supported gain values (1): 0.0 ---------------- What could be the reason for this? What else should I try? --gv
I just received a Product Announcement from SILICON LABS. There new TV Tuner Chip, the Si2177, appears to be able to demodulate Analog TV directly on the chip without software. If I am not mistaken, this function is a new feature in TV Tuner Chips, which may provide a much better SDR than current TV Tuner Chip Dongles, especially when it comes to noise performance. It also eliminates almost all external components. RF Input Frequency Range - 42 to 870 MHz Si2177 5th Generation Silicon TV Tuner ICs http://www.silabs.com/Support%20Documents/TechnicalDocs/Si2177-short.pdf
It seems the chip does not output the raw I and Q values... It means there is nothing to do with it except watching tv, exactly the converse of existing tuners ;-) regards sylvain 2013/9/19 Jay Salsburg <jsalsburg@bellsouth.net>
I just received a Product Announcement from SILICON LABS. There new TV Tuner Chip, the Si2177, appears to be able to demodulate Analog TV directly on the chip without software. If I am not mistaken, this function is a new feature in TV Tuner Chips, which may provide a much better SDR than current TV Tuner Chip Dongles, especially when it comes to noise performance. It also eliminates almost all external components. RF Input Frequency Range - 42 to 870 MHz
Si2177 5th Generation Silicon TV Tuner ICs
http://www.silabs.com/Support%20Documents/TechnicalDocs/Si2177-short.pdf
OK, for those who do not grasp the principle of On-chip Demodulation, SILICON LABS is manufacturing a spectrum of advanced Tuners, one of which may suit the mindset of those who buck the idea of a Demodulator on chip. There is one that demodulates Analog TV alone, one that demodulates Digital TV alone, and one that does both. Ask yourself this question... Why is there an A/D converter chip on the current Tuner Dongles? Would it not be better to convert the unadulterated demodulated Digital stream directly into a 192k/24bit audio card (or just 48k/16bit)? This new capability tells my Engineering mind that the noise floor would go way down, which is the main deficiency with the current cheap TV Tuner Dongles, keeping them from being used for low level narrowband reception. http://www.silabs.com/Support%20Documents/TechnicalDocs/Si2157-short.pdf -----Original Message----- From: osmocom-sdr-bounces@lists.osmocom.org [mailto:osmocom-sdr-bounces@lists.osmocom.org] On Behalf Of Jay Salsburg Sent: Thursday, September 19, 2013 12:21 PM To: osmocom-sdr@lists.osmocom.org Subject: new TV Tuner Chip, the Si2177 I just received a Product Announcement from SILICON LABS. There new TV Tuner Chip, the Si2177, appears to be able to demodulate Analog TV directly on the chip without software. If I am not mistaken, this function is a new feature in TV Tuner Chips, which may provide a much better SDR than current TV Tuner Chip Dongles, especially when it comes to noise performance. It also eliminates almost all external components. RF Input Frequency Range - 42 to 870 MHz Si2177 5th Generation Silicon TV Tuner ICs http://www.silabs.com/Support%20Documents/TechnicalDocs/Si2177-short.pdf ----- No virus found in this message. Checked by AVG - www.avg.com Version: 2013.0.3408 / Virus Database: 3222/6680 - Release Date: 09/19/13
On 9/20/13, Jay Salsburg <jsalsburg@bellsouth.net> wrote:
OK, for those who do not grasp the principle of On-chip Demodulation,
other way around
There is one that demodulates Analog TV alone, one that demodulates Digital TV alone, and one that does both.
RF --> black box --> video pixels while we want RF --> A/D --> data stream or fancy RF --> A/D --> DSP --> data stream
Ask yourself this question... Why is there an A/D converter chip on the current Tuner Dongles?
because we forgot how to do magic
Would it not be better to convert the unadulterated
umm what?
demodulated
demodulated by what? from what modulation? this is what SDR is about (flexibility)
Digital stream directly into a 192k/24bit audio card (or just 48k/16bit)?
why would you want to analog sample digital stream?
This new capability tells my Engineering mind
no -- Who logs in to gdm? Not I, said the duck.
The bandwidth of the I/Q pair is too large to be transmitted over USB for the reception of TV signals. After demodulation the bandwidth is lower so it would (marginally) fit an USB interface if we talk about traditional analogue TV. For digital TV the bandwidth reduction by the decoder is much larger. I would not be surprised if the Si Labs chips have an option to send unprocessed I/Q data to the USB. Somebody should approach them and ask:-) 73 Leif / SM5BSZ
OK, for those who do not grasp the principle of On-chip Demodulation, SILICON LABS is manufacturing a spectrum of advanced Tuners, one of which may suit the mindset of those who buck the idea of a Demodulator on chip. There is one that demodulates Analog TV alone, one that demodulates Digital TV alone, and one that does both. Ask yourself this question... Why is there an A/D converter chip on the current Tuner Dongles? Would it not be better to convert the unadulterated demodulated Digital stream directly into a 192k/24bit audio card (or just 48k/16bit)? This new capability tells my Engineering mind that the noise floor would go way down, which is the main deficiency with the current cheap TV Tuner Dongles, keeping them from being used for low level narrowband reception.
http://www.silabs.com/Support%20Documents/TechnicalDocs/Si2157-short.pdf
-----Original Message----- From: osmocom-sdr-bounces@lists.osmocom.org [mailto:osmocom-sdr-bounces@lists.osmocom.org] On Behalf Of Jay Salsburg Sent: Thursday, September 19, 2013 12:21 PM To: osmocom-sdr@lists.osmocom.org Subject: new TV Tuner Chip, the Si2177
I just received a Product Announcement from SILICON LABS. There new TV Tuner Chip, the Si2177, appears to be able to demodulate Analog TV directly on the chip without software. If I am not mistaken, this function is a new feature in TV Tuner Chips, which may provide a much better SDR than current TV Tuner Chip Dongles, especially when it comes to noise performance. It also eliminates almost all external components. RF Input Frequency Range - 42 to 870 MHz
Si2177 5th Generation Silicon TV Tuner ICs
http://www.silabs.com/Support%20Documents/TechnicalDocs/Si2177-short.pdf
----- No virus found in this message. Checked by AVG - www.avg.com Version: 2013.0.3408 / Virus Database: 3222/6680 - Release Date: 09/19/13
On Sat, 21 Sep 2013 02:43:14 +0200 Leif Asbrink <leif@sm5bsz.com> wrote:
The bandwidth of the I/Q pair is too large to be transmitted over USB for the reception of TV signals. After demodulation the bandwidth is lower so it would (marginally) fit an USB interface if we talk about traditional analogue TV. For digital TV the bandwidth reduction by the decoder is much larger.
How much is actually needed? You know there's USB 3 these days, which can transmit about a megabit with some change (due to overhead). -- Pete
The bandwidth of the I/Q pair is too large to be transmitted over USB for the reception of TV signals. After demodulation the bandwidth is lower so it would (marginally) fit an USB interface if we talk about traditional analogue TV. For digital TV the bandwidth reduction by the decoder is much larger.
Is that correct? From what I can find, an analogue TV signal has a bandwidth of around 6-8MHz. The HackRF is an SDR that works over USB2.0 and can capture a chunk of RF spectrum up to 20MHz, which should be ample for one analogue (or even digital) TV signal, perhaps even two if the channels are close enough together.
How much is actually needed? You know there's USB 3 these days, which can transmit about a megabit with some change (due to overhead).
A megabit? :-) USB3.0 has a signalling rate of 5Gbps and according to Wikipedia, a usable data rate of up to 4Gbps. If you can fit 20MHz of RF over USB2.0 at 480Mbps, you should be able to start approaching 200MHz of bandwidth with a USB3.0 SDR! Cheers, Adam.
On 9/21/13, Adam Nielsen <a.nielsen@shikadi.net> wrote:
From what I can find, an analogue TV signal has a bandwidth of around 6-8MHz. The HackRF is an SDR that works over USB2.0 and can capture a chunk of RF spectrum up to 20MHz, which should be ample for one analogue (or even digital) TV signal, perhaps even two if the channels are close enough together.
USB 2.0 has no problem with 30MB/s, and if you take care of all the quirks (only 1 device, no programs running, "turbo mode" aka >1MB bulk transfers) you can go up to ~40MB/s
How much is actually needed? You know there's USB 3 these days, which can transmit about a megabit with some change (due to overhead).
A megabit? :-) USB3.0 has a signalling rate of 5Gbps and according to Wikipedia, a usable data rate of up to 4Gbps. If you can fit 20MHz of RF over USB2.0 at 480Mbps, you should be able to start approaching 200MHz of bandwidth with a USB3.0 SDR!
Cypress FX3 does 360MB/s in real life. -- Who logs in to gdm? Not I, said the duck.
Hi Adam,
The bandwidth of the I/Q pair is too large to be transmitted over USB for the reception of TV signals. After demodulation the bandwidth is lower so it would (marginally) fit an USB interface if we talk about traditional analogue TV. For digital TV the bandwidth reduction by the decoder is much larger.
Is that correct? From what I can find, an analogue TV signal has a bandwidth of around 6-8MHz. Yes.
The HackRF is an SDR that works over USB2.0 and can capture a chunk of RF spectrum up to 20MHz, which should be ample for one analogue (or even digital) TV signal, perhaps even two if the channels are close enough together.
I was under the impression that the USB channel was the reason that the highest sampling rate I was aware of in continous mode is 4 MHz (QS1R) Now, I did not think of the fact that for the dongle we need only 8 bit while normal SDRs use 16 bit so with my assumption the maximum sampling speed would be 8 MHz. To receive 6-8 MHz bandwidth one would need to sample quite a bit higher. Surely one could apply digital filters but even so a, substantial amount of oversampling is needed. Are you sure HackRF really can send 20 MHz of bandwidth over USB 2.0 continously? Where did you find that info? (Seems I should try to push SDR manufacturers who use USB 2.0 to supply modes with higher sampling rates...) 73 Leif
HackRF sends 8bit samples, same as the RTL dongle. 20Msps * 8bits * 2 (complex sampling) = 320Mbit/s, or 67% utilization. The Ettus B100 gets 10.6Msps on most USB host controllers, sometimes 12.8Msps if you have a really nice USB host controller with nothing else on the bus -- 71-85% utilization with 16bit samples. You can double that if you select 8 bit sampling mode for the B100, for 21.3-25.6Msps, at the cost of dynamic range. The RTL dongle appears not to be able to continuously sample above 2.4Msps for reasons that are unclear to me, but certainly not due to a USB2.0 limitation. --n On Sat, Sep 21, 2013 at 2:37 PM, Leif Asbrink <leif@sm5bsz.com> wrote:
Hi Adam,
The bandwidth of the I/Q pair is too large to be transmitted over USB for the reception of TV signals. After demodulation the bandwidth is lower so it would (marginally) fit an USB interface if we talk about traditional analogue TV. For digital TV the bandwidth reduction by the decoder is much larger.
Is that correct? From what I can find, an analogue TV signal has a bandwidth of around 6-8MHz. Yes.
The HackRF is an SDR that works over USB2.0 and can capture a chunk of RF spectrum up to 20MHz, which should be ample for one analogue (or even digital) TV signal, perhaps even two if the channels are close enough together.
I was under the impression that the USB channel was the reason that the highest sampling rate I was aware of in continous mode is 4 MHz (QS1R) Now, I did not think of the fact that for the dongle we need only 8 bit while normal SDRs use 16 bit so with my assumption the maximum sampling speed would be 8 MHz. To receive 6-8 MHz bandwidth one would need to sample quite a bit higher. Surely one could apply digital filters but even so a, substantial amount of oversampling is needed.
Are you sure HackRF really can send 20 MHz of bandwidth over USB 2.0 continously? Where did you find that info? (Seems I should try to push SDR manufacturers who use USB 2.0 to supply modes with higher sampling rates...)
73
Leif
What is all this talk about USB. High-end Audio Interfaces digitize/quantize at 192KHz/24bit. Since these new Tuners are almost naked on a surface mount board, all that is needed other than a good audio card is a BusPirate to control the I2C to get one of these new Analog TV tuner Chips to work as a SDR. Since most "Intelligence" in radio is narrow band typically a Voice Channel, all that a wideband A/D gives you is a view from 50,000 feet of the spectrum which is OK for Test and Measurement. I cannot use my TV Dongles for most of my (Forward Scatter RADAR) applications because of their low resolution, I must use a conventional Scanner because it converts the signal to Audio. What I need is high definition and narrow band, the current Dongles are typically Wide Band low resolution (2Mhz/8bit). This is why a Tuner Chip with low noise and demodulated analog output is attractive to me, it is a complete solution. -----Original Message----- From: osmocom-sdr-bounces@lists.osmocom.org [mailto:osmocom-sdr-bounces@lists.osmocom.org] On Behalf Of Leif Asbrink Sent: Saturday, September 21, 2013 4:38 PM To: osmocom-sdr@lists.osmocom.org Subject: Re: new TV Tuner Chip, the Si2177 Hi Adam,
The bandwidth of the I/Q pair is too large to be transmitted over USB for the reception of TV signals. After demodulation the bandwidth is lower so it would (marginally) fit an USB interface if we talk about traditional analogue TV. For digital TV the bandwidth reduction by the decoder is much larger.
Is that correct? From what I can find, an analogue TV signal has a bandwidth of around 6-8MHz. Yes.
The HackRF is an SDR that works over USB2.0 and can capture a chunk of RF spectrum up to 20MHz, which should be ample for one analogue (or even digital) TV signal, perhaps even two if the channels are close enough together.
I was under the impression that the USB channel was the reason that the highest sampling rate I was aware of in continous mode is 4 MHz (QS1R) Now, I did not think of the fact that for the dongle we need only 8 bit while normal SDRs use 16 bit so with my assumption the maximum sampling speed would be 8 MHz. To receive 6-8 MHz bandwidth one would need to sample quite a bit higher. Surely one could apply digital filters but even so a, substantial amount of oversampling is needed. Are you sure HackRF really can send 20 MHz of bandwidth over USB 2.0 continously? Where did you find that info? (Seems I should try to push SDR manufacturers who use USB 2.0 to supply modes with higher sampling rates...) 73 Leif ----- No virus found in this message. Checked by AVG - www.avg.com Version: 2013.0.3408 / Virus Database: 3222/6687 - Release Date: 09/21/13
As others have tried to explain, this chip does not provide an analog output for you to digitize with your soundcard. It turns RF into H.264 digital video. That's all. There's nothing to digitize and no place to plug your soundcard into. --n What is all this talk about USB. High-end Audio Interfaces digitize/quantize at 192KHz/24bit. Since these new Tuners are almost naked on a surface mount board, all that is needed other than a good audio card is a BusPirate to control the I2C to get one of these new Analog TV tuner Chips to work as a SDR. Since most "Intelligence" in radio is narrow band typically a Voice Channel, all that a wideband A/D gives you is a view from 50,000 feet of the spectrum which is OK for Test and Measurement. I cannot use my TV Dongles for most of my (Forward Scatter RADAR) applications because of their low resolution, I must use a conventional Scanner because it converts the signal to Audio. What I need is high definition and narrow band, the current Dongles are typically Wide Band low resolution (2Mhz/8bit). This is why a Tuner Chip with low noise and demodulated analog output is attractive to me, it is a complete solution. -----Original Message----- From: osmocom-sdr-bounces@lists.osmocom.org [mailto:osmocom-sdr-bounces@lists.osmocom.org] On Behalf Of Leif Asbrink Sent: Saturday, September 21, 2013 4:38 PM To: osmocom-sdr@lists.osmocom.org Subject: Re: new TV Tuner Chip, the Si2177 Hi Adam,
The bandwidth of the I/Q pair is too large to be transmitted over USB for the reception of TV signals. After demodulation the bandwidth is lower so it would (marginally) fit an USB interface if we talk about traditional analogue TV. For digital TV the bandwidth reduction by the decoder is much larger.
Is that correct? From what I can find, an analogue TV signal has a bandwidth of around 6-8MHz. Yes.
The HackRF is an SDR that works over USB2.0 and can capture a chunk of RF spectrum up to 20MHz, which should be ample for one analogue (or even digital) TV signal, perhaps even two if the channels are close enough together.
I was under the impression that the USB channel was the reason that the highest sampling rate I was aware of in continous mode is 4 MHz (QS1R) Now, I did not think of the fact that for the dongle we need only 8 bit while normal SDRs use 16 bit so with my assumption the maximum sampling speed would be 8 MHz. To receive 6-8 MHz bandwidth one would need to sample quite a bit higher. Surely one could apply digital filters but even so a, substantial amount of oversampling is needed. Are you sure HackRF really can send 20 MHz of bandwidth over USB 2.0 continously? Where did you find that info? (Seems I should try to push SDR manufacturers who use USB 2.0 to supply modes with higher sampling rates...) 73 Leif ----- No virus found in this message. Checked by AVG - www.avg.com Version: 2013.0.3408 / Virus Database: 3222/6687 - Release Date: 09/21/13
All, I am using hackrf currently to receive LTE downlink at 15.36Msps. I have not specifically tried it at 20Msps, but I believe it should work. USB2.0 is certainly not the limiting factor for the rtl dongles' sample rate. Ben On Sep 21, 2013 5:05 PM, "Nick Foster" <bistromath@gmail.com> wrote:
As others have tried to explain, this chip does not provide an analog output for you to digitize with your soundcard. It turns RF into H.264 digital video. That's all. There's nothing to digitize and no place to plug your soundcard into.
--n What is all this talk about USB. High-end Audio Interfaces digitize/quantize at 192KHz/24bit. Since these new Tuners are almost naked on a surface mount board, all that is needed other than a good audio card is a BusPirate to control the I2C to get one of these new Analog TV tuner Chips to work as a SDR. Since most "Intelligence" in radio is narrow band typically a Voice Channel, all that a wideband A/D gives you is a view from 50,000 feet of the spectrum which is OK for Test and Measurement. I cannot use my TV Dongles for most of my (Forward Scatter RADAR) applications because of their low resolution, I must use a conventional Scanner because it converts the signal to Audio. What I need is high definition and narrow band, the current Dongles are typically Wide Band low resolution (2Mhz/8bit). This is why a Tuner Chip with low noise and demodulated analog output is attractive to me, it is a complete solution.
-----Original Message----- From: osmocom-sdr-bounces@lists.osmocom.org [mailto:osmocom-sdr-bounces@lists.osmocom.org] On Behalf Of Leif Asbrink Sent: Saturday, September 21, 2013 4:38 PM To: osmocom-sdr@lists.osmocom.org Subject: Re: new TV Tuner Chip, the Si2177
Hi Adam,
The bandwidth of the I/Q pair is too large to be transmitted over USB for the reception of TV signals. After demodulation the bandwidth is lower so it would (marginally) fit an USB interface if we talk about traditional analogue TV. For digital TV the bandwidth reduction by the decoder is much larger.
Is that correct? From what I can find, an analogue TV signal has a bandwidth of around 6-8MHz. Yes.
The HackRF is an SDR that works over USB2.0 and can capture a chunk of RF spectrum up to 20MHz, which should be ample for one analogue (or even digital) TV signal, perhaps even two if the channels are close enough together.
I was under the impression that the USB channel was the reason that the highest sampling rate I was aware of in continous mode is 4 MHz (QS1R) Now, I did not think of the fact that for the dongle we need only 8 bit while normal SDRs use 16 bit so with my assumption the maximum sampling speed would be 8 MHz. To receive 6-8 MHz bandwidth one would need to sample quite a bit higher. Surely one could apply digital filters but even so a, substantial amount of oversampling is needed.
Are you sure HackRF really can send 20 MHz of bandwidth over USB 2.0 continously? Where did you find that info? (Seems I should try to push SDR manufacturers who use USB 2.0 to supply modes with higher sampling rates...)
73
Leif
----- No virus found in this message. Checked by AVG - www.avg.com Version: 2013.0.3408 / Virus Database: 3222/6687 - Release Date: 09/21/13
My personal tests on usb2 with Windows or Linux show a limit around 35 mbytes/sec (tested with Cypress fx2 or fx3) Sylvain Le 22 sept. 2013 18:36, "Ben Wojtowicz" <bwojtowi@gmail.com> a écrit :
All,
I am using hackrf currently to receive LTE downlink at 15.36Msps. I have not specifically tried it at 20Msps, but I believe it should work. USB2.0 is certainly not the limiting factor for the rtl dongles' sample rate.
Ben On Sep 21, 2013 5:05 PM, "Nick Foster" <bistromath@gmail.com> wrote:
As others have tried to explain, this chip does not provide an analog output for you to digitize with your soundcard. It turns RF into H.264 digital video. That's all. There's nothing to digitize and no place to plug your soundcard into.
--n What is all this talk about USB. High-end Audio Interfaces digitize/quantize at 192KHz/24bit. Since these new Tuners are almost naked on a surface mount board, all that is needed other than a good audio card is a BusPirate to control the I2C to get one of these new Analog TV tuner Chips to work as a SDR. Since most "Intelligence" in radio is narrow band typically a Voice Channel, all that a wideband A/D gives you is a view from 50,000 feet of the spectrum which is OK for Test and Measurement. I cannot use my TV Dongles for most of my (Forward Scatter RADAR) applications because of their low resolution, I must use a conventional Scanner because it converts the signal to Audio. What I need is high definition and narrow band, the current Dongles are typically Wide Band low resolution (2Mhz/8bit). This is why a Tuner Chip with low noise and demodulated analog output is attractive to me, it is a complete solution.
-----Original Message----- From: osmocom-sdr-bounces@lists.osmocom.org [mailto:osmocom-sdr-bounces@lists.osmocom.org] On Behalf Of Leif Asbrink Sent: Saturday, September 21, 2013 4:38 PM To: osmocom-sdr@lists.osmocom.org Subject: Re: new TV Tuner Chip, the Si2177
Hi Adam,
The bandwidth of the I/Q pair is too large to be transmitted over USB for the reception of TV signals. After demodulation the bandwidth is lower so it would (marginally) fit an USB interface if we talk about traditional analogue TV. For digital TV the bandwidth reduction by the decoder is much larger.
Is that correct? From what I can find, an analogue TV signal has a bandwidth of around 6-8MHz. Yes.
The HackRF is an SDR that works over USB2.0 and can capture a chunk of RF spectrum up to 20MHz, which should be ample for one analogue (or even digital) TV signal, perhaps even two if the channels are close enough together.
I was under the impression that the USB channel was the reason that the highest sampling rate I was aware of in continous mode is 4 MHz (QS1R) Now, I did not think of the fact that for the dongle we need only 8 bit while normal SDRs use 16 bit so with my assumption the maximum sampling speed would be 8 MHz. To receive 6-8 MHz bandwidth one would need to sample quite a bit higher. Surely one could apply digital filters but even so a, substantial amount of oversampling is needed.
Are you sure HackRF really can send 20 MHz of bandwidth over USB 2.0 continously? Where did you find that info? (Seems I should try to push SDR manufacturers who use USB 2.0 to supply modes with higher sampling rates...)
73
Leif
----- No virus found in this message. Checked by AVG - www.avg.com Version: 2013.0.3408 / Virus Database: 3222/6687 - Release Date: 09/21/13
Hi Ben!
I am using hackrf currently to receive LTE downlink at 15.36Msps. I have not specifically tried it at 20Msps, but I believe it should work. USB2.0 is certainly not the limiting factor for the rtl dongles' sample rate.
Very interesting. Is there somewhere one can buy the hackrf hardware? Leif
There is also the bladeRF hardware, which is available and in stock. I have a unit and it is a very nice piece of kit. It achieves 40 MS/s @ 12 bit over USB 3.0. It uses a Cypress FX3, so even on USB 2 it should be able to saturate the bus. Unfortunately, the price went way up after their Kickstarter ended. Also, the SW is still in development and not polished yet. -Scott On 9/22/2013 1:34 PM, Adam Nielsen wrote:
Very interesting. Is there somewhere one can buy the hackrf hardware? Probably not until sometime after Jan/Feb 2014 when all the units ordered through the Kickstarter campaign have hopefully shipped.
Cheers, Adam.
There is also the bladeRF hardware, which is available and in stock. I have a unit and it is a very nice piece of kit. It achieves 40 MS/s @ 12 bit over USB 3.0. It uses a Cypress FX3, so even on USB 2 it should be able to saturate the bus. Unfortunately, the price went way up after their Kickstarter ended. Also, the SW is still in development and not polished yet.
Just to confirm, are you saying you can use the bladeRF as a proper SDR like the RTL devices? I did look at it a while back, but to me it looked like it required all the SDR processing to happen within an onboard FPGA, so I assumed it wasn't a PC-based SDR. Cheers, Adam.
Hi Adam, The bladeRF can be configured to send I/Q data at the desired bandwidth to the PC. Surely it can be configured to do many other things also. It all depends on how clever software designers are and to what extent help is available. I will order a unit. Maybe I will be able to get it running in Linrad. If so, it would probably allow the widest bandwidth of all harwdare currently supported. 73 Leif / SM5BSZ
There is also the bladeRF hardware, which is available and in stock. I have a unit and it is a very nice piece of kit. It achieves 40 MS/s @ 12 bit over USB 3.0. It uses a Cypress FX3, so even on USB 2 it should be able to saturate the bus. Unfortunately, the price went way up after their Kickstarter ended. Also, the SW is still in development and not polished yet.
Just to confirm, are you saying you can use the bladeRF as a proper SDR like the RTL devices? I did look at it a while back, but to me it looked like it required all the SDR processing to happen within an onboard FPGA, so I assumed it wasn't a PC-based SDR.
Cheers, Adam.
Hello Leif,
I will order a unit. Maybe I will be able to get it running in Linrad. If so, it would probably allow the widest bandwidth of all harwdare currently supported.
How useful is such a "wide bandwidth" for users ? How many of them really need such a wide bandwidth ? Up to now it always looked like users were mostly interested in single channels. I am new to this list and don't know what others are doing. The other reason I am asking is because I have got a very different device with a bandwidth of 100 MHz running and I wonder if I am the only one playing with such things. My device is an ADLINK digitizer PCIe-9842: http://www.adlinktech.com/PD/photo/display/PCIe-9842/PCIe-9842_bimg_1.jpg This digitizer can sample at 200 MHz on a single input channel. So this is very different from the other devices that are discussed here: No antenna amplifier, no mixer, no AGC. At 200 MS/s it is hard to emulate all the missing hardware parts in software. Since there is no mixer, the software can demodulate only frequencies in the range of public radio stations (short wave). Would it make sense to have Linrad support such a device ? Or is this device just too limited to be of interest ?
How useful is such a "wide bandwidth" for users ?
It depends what you are trying to examine. If you want to look at TV signals you need 8MHz, if you want to look at 802.11n you need 40-80MHz, 160MHz for 802.11ac, etc. Many people are interested in implementing these protocols entirely in software for many reasons, many revolving around security.
How many of them really need such a wide bandwidth ?
The wider the better, simply for flexibility. The wider the bandwidth the less the need for frequency hopping if you can receive all relevant frequencies at once. This is why there are relatively frequent questions about combining multiple devices to extend the available bandwidth. It looks like the HackRF's external clock input will make it one of the first low cost devices that can do this.
Up to now it always looked like users were mostly interested in single channels. I am new to this list and don't know what others are doing.
Up to now it was only really practical to listen to a single channel. The Realtek 2832 dongles are the first to make it practical to listen to multiple channels, but a lot of SDR software still needs to catch up.
My device is an ADLINK digitizer PCIe-9842:
That is very interesting! I will leave others to comment on the viability of devices like this for SDR purposes. Cheers, Adam.
Hi Jürgen,
How useful is such a "wide bandwidth" for users ? It allows efficient removal of strong static rain QRN.
How many of them really need such a wide bandwidth ? On VHF bands I would say 80% or more, but only a during rain summertime, and only when the raindrops are charged.
Have a look at the lower left corner of figure 1 here: http://www.sm5bsz.com/lir/recordings/static-rain.htm There you can see the sequence of pulses that originate from one raindrop hitting one of the elements of a yagi array. The sampling speed is 2 MHz and it is not quite enough. The pulses immediately after the first discharge are not resolved. At a speed of 96 kHz the entire time period is a noise burst that can only be removed by gating out the entire time span. When the number of raindrops increases, 96 kHz does not work because the noise bursts would overlap. I would think 5 MHz would be about optimum (with todays computer hardware and Linrad.) It would allow removal of S9+20 dB noise from static rain and give the normal noise floor with no adverse effect on weak or strong signals. With the very high bandwidth one might discover that there is (removable) noise from charged dust whenever winds are high in dry weather. I do not know, but the static rain statement is based on solid experience with an equivalent wideband blanker (5 or 10 MHz wide) that I was using many years ago: http://www.sm5bsz.com/rtblnk/rt0669.htm
Up to now it always looked like users were mostly interested in single channels. I am new to this list and don't know what others are doing.
The other reason I am asking is because I have got a very different device with a bandwidth of 100 MHz running and I wonder if I am the only one playing with such things. My device is an ADLINK digitizer PCIe-9842:
http://www.adlinktech.com/PD/photo/display/PCIe-9842/PCIe-9842_bimg_1.jpg
This digitizer can sample at 200 MHz on a single input channel. So this is very different from the other devices that are discussed here: No antenna amplifier, no mixer, no AGC. At 200 MS/s it is hard to emulate all the missing hardware parts in software. Since there is no mixer, the software can demodulate only frequencies in the range of public radio stations (short wave). Would it make sense to have Linrad support such a device ? Or is this device just too limited to be of interest ? Yes:-) I did not know about this card although it seems to come from a Swedish company. I will call them tomorrow:-)
73 Leif / SM5BSZ
Hello Leif,
How useful is such a "wide bandwidth" for users ? It allows efficient removal of strong static rain QRN.
This is an aspect that is completely new to me. I was guessing more in the direction of recording hundreds of channels simultaneously.
How many of them really need such a wide bandwidth ? On VHF bands I would say 80% or more, but only a during rain summertime, and only when the raindrops are charged.
Have a look at the lower left corner of figure 1 here: http://www.sm5bsz.com/lir/recordings/static-rain.htm
There you can see the sequence of pulses that originate from one raindrop hitting one of the elements of a yagi array. The sampling speed is 2 MHz and it is not quite enough. The pulses immediately after the first discharge are not resolved.
That's funny. Charged raindrops causing pulses. But it makes sense that a higher sampling rate can simply removal of such disturbances. A sampling rate of 5 to 10 MHz is easily implemented with the PCIe-9842. My first trials with my own software used 5 and later 20 MHz. At the moment, my recordings use 200 MHz by default. Thanks to the PCI express interface and a good driver software, the transfer of 400 MB/s puts no load onto the CPU. It is only the signal processing that causes a high computational burden onto the hardware. Up to now I have processed the data from the PCIe-9842 with my own channelizer software. For example, in the medium wave range of radio stations between 522 kHz and 1656 kHz there are 127 channels spaced in a 9 kHz raster. My software demodulates all of them simultaneously (AM) and saves the data of all channels into one .wav file. This .wav file can be processed later with the Audacity sound editor, the only editor I know that can handle 127 channels with PCM data. The signal processing of the channelizer runs on my graphics card (nvidia GTX 660TI with 1344 GPU cores). I guess that the noise removal for the raindrops can also be done on the graphics card, even with 200 MHz.
My device is an ADLINK digitizer PCIe-9842:
http://www.adlinktech.com/PD/photo/display/PCIe-9842/PCIe-9842_bimg_1.jpg
This digitizer can sample at 200 MHz on a single input channel. So this is very different from the other devices that are discussed here: No antenna amplifier, no mixer, no AGC. At 200 MS/s it is hard to emulate all the missing hardware parts in software. Since there is no mixer, the software can demodulate only frequencies in the range of public radio stations (short wave). Would it make sense to have Linrad support such a device ? Or is this device just too limited to be of interest ? Yes:-) I did not know about this card although it seems to come from a Swedish company. I will call them tomorrow:-)
ADLINK is a taiwanese company, as far as I know. The Swedish company you mean is probably Strategic Test in Stockholm. They offer excellent cards with Linux support, but too expensive for me. I have downloaded the source code of Linrad and had a short look at it. Why don't you put the source code into a Subversion repository at SourceForge ? Storing the source code there costs nothing and simplifies access. It looks like there is a systematic way of integrating new devices into the Linrad source code. If I tried to integrate the PCIe-9842, would you consider my source code for acceptance to into Linrad ?
The signal processing of the channelizer runs on my graphics card (nvidia GTX 660TI with 1344 GPU cores). I guess that the noise removal for the raindrops can also be done on the graphics card, even with 200 MHz.
This is something I am *very* interested in. How do you do the processing on the GPU? Do you use OpenGL, OpenCL, CUDA, etc? Did you write the code yourself or are you using an existing GPGPU library? What sort of performance do you get?
Why don't you put the source code into a Subversion repository at SourceForge ? Storing the source code there costs nothing and simplifies access.
Or you could use GitHub - having used SourceForge and GitHub, GitHub is a lot easier to set up, providing you are already familiar with Git of course! Cheers, Adam.
Hello Adam,
The signal processing of the channelizer runs on my graphics card (nvidia GTX 660TI with 1344 GPU cores). I guess that the noise removal for the raindrops can also be done on the graphics card, even with 200 MHz. This is something I am *very* interested in. How do you do the processing on the GPU? Do you use OpenGL, OpenCL, CUDA, etc? Did you write the code yourself or are you using an existing GPGPU library?
I use OpenCL (no OpenGL), only the C level API, not the C++ level API. I have tested my software against the OpenCL- implementations of nvidia, AMD, and also Intel (). This was hard work but the channelizer is really portable now. When I began, I hoped that I could use an existing GPGPU library, but such libraries usually suplly some kind of FFT and that's all about signal processing they offer. There is no library available for channelizer or filtering with FIR or IIR that I am aware of. Therefore I wrote the source code myself and decided to do it with real-valued signals (since I sample the antenna directly) and not with complex-valued signals that are commonplace in the SDR community.
What sort of performance do you get?
This is hard to tell in numbers since there are so many parameters that can be tuned. One example: The demodulated short-wave signals are saved in a .wav file with all audio channels with 16 bit PCM at 8 kHz. I have tested increasing the audio output sample rate to 44.1 kHz. The sound quality improved significantly and I liked this quality. But this sound quality comes at a high price: a 5 fold increase in GPU load. My channelizer uses real-valued Goertzel filters and not the usual FFT. Therefore the GPU load increases with the number of channels used. Channelizers based on the usual FFT would be faster whenever the number of channels is known in advance to be a power of 2. There are many other design decisions like this that influence performance. As a rough estimate about what the graphics card can do: With an input sample rate of 200 MHz (1 channel, 16 bit) and an audio output sample rate of 8 kHz (for each channel, 16 bit) the channelizer can process more than 120 channels. At that rate there is no buffer overflow.
Why don't you put the source code into a Subversion repository at SourceForge ? Storing the source code there costs nothing and simplifies access. Or you could use GitHub - having used SourceForge and GitHub, GitHub is a lot easier to set up, providing you are already familiar with Git of course!
Indeed, "providing you are already familiar with Git" is usually an obstacle. Most developers don't want to learn repo management. Therefore I prefer Subversion. But this thread is not the right place for discussing personal preferences about SCM systems. My main point is this: Is there an existing SDR tool fit for handling data that comes in at 200 MS/s ? Thanks for your comments and suggestions.
Hello Jürgen,
That's funny. Charged raindrops causing pulses. But it makes sense that a higher sampling rate can simply removal of such disturbances. A sampling rate of 5 to 10 MHz is easily implemented with the PCIe-9842. My first trials with my own software used 5 and later 20 MHz. At the moment, my recordings use 200 MHz by default. Thanks to the PCI express interface and a good driver software, the transfer of 400 MB/s puts no load onto the CPU. It is only the signal processing that causes a high computational burden onto the hardware. Very interesting:-)
Linrad can process 8 MHz bandwidth when run without the noise blanker on my now old super-computer, an Intel D5400XS board with two 2 Xeon E5410 CPUs and 8 cpu cores while producing decent filtering. With the noise blanker enabled it can do 4 MHz. If I apply less good filters Linrad can do at least twice the bandwidths. The limitation is the time to do FFT. I guess that could be moved to a GPU but I have no idea about how difficult it might be. Linrad goes back and forth between the time and the frequency domain. Four FFT computations are done after one another for the noise blanker and they are placed in separate threads. The blanker FFTs are double but placed in the same thread and for that reason the blanker fills up a core at half the bandwidth. That should not be too difficult to fix but I never had any reason. I have not yet had access to any high speed hardware...
ADLINK is a taiwanese company, as far as I know. The Swedish company you mean is probably Strategic Test in Stockholm. They offer excellent cards with Linux support, but too expensive for me. No, it was another Swedish company. I called them today but the price they asked was pretty expensive so I did not order.
I have downloaded the source code of Linrad and had a short look at it. Why don't you put the source code into a Subversion repository at SourceForge ? Storing the source code there costs nothing and simplifies access. That is because I have no idea how to do it. I do not want to spend time on learning those kinds of things. I have several far more exciting things on my agenda:-)
It looks like there is a systematic way of integrating new devices into the Linrad source code. If I tried to integrate the PCIe-9842, would you consider my source code for acceptance to into Linrad ? Absolutely. I would be delighted:-) If you report sucess I would also want to buy such a card even if I would have to pay more than I really want for it. On the Internet I find the price to be something like 2000 Euro.
Regards Leif
Hello Leif,
The limitation is the time to do FFT. I guess that could be moved to a GPU but I have no idea about how difficult it might be.
Using the GPU to do only the FFT would be a gentle way to introduce the GPU into Linrad. But only if the interface to the FFT is clean enough.
I have downloaded the source code of Linrad and had a short look at it. Why don't you put the source code into a Subversion repository at SourceForge ? Storing the source code there costs nothing and simplifies access. That is because I have no idea how to do it. I do not want to spend time on learning those kinds of things. I have several far more exciting things on my agenda:-)
Ok, setting up a repo is something that I could do. But after setting it up it must be clear that the primary source code is now in the repo and not on your local disk. The repo is a safe place where to get the latest/primary source code and also each earlier revision (if needed).
It looks like there is a systematic way of integrating new devices into the Linrad source code. If I tried to integrate the PCIe-9842, would you consider my source code for acceptance to into Linrad ? Absolutely. I would be delighted:-) If you report sucess I would also want to buy such a card even if I would have to pay more than I really want for it. On the Internet I find the price to be something like 2000 Euro.
2000 Euro + VAT is what I paid here in Germany. Much money but still inexpensive in comparison to the industry.
Hello Jürgen!
Using the GPU to do only the FFT would be a gentle way to introduce the GPU into Linrad. But only if the interface to the FFT is clean enough. It would have to be rewritten. There is a large number of FFT implementations depending on the input format. It will be easy to add more and to select the GPU if available.
I have downloaded the source code of Linrad and had a short look at it. Why don't you put the source code into a Subversion repository at SourceForge ? Storing the source code there costs nothing and simplifies access. That is because I have no idea how to do it. I do not want to spend time on learning those kinds of things. I have several far more exciting things on my agenda:-)
Ok, setting up a repo is something that I could do. But after setting it up it must be clear that the primary source code is now in the repo and not on your local disk. The repo is a safe place where to get the latest/primary source code and also each earlier revision (if needed). This would be perfectly fine with me.
The worries I have are about a new build system with CMake. I do not know the implications...
2000 Euro + VAT is what I paid here in Germany. Much money but still inexpensive in comparison to the industry. OK. I ordered one today. Delivery time 3 or 4 weeks.
- Leif -
Yes, as Leif says, the unit works just fine as a passthru device. I already have it working with my own SDR program. It supports TX as well, though I haven't tested that aspect yet. I doubt I'll make use of the FPGA personally; while cool, I want my program to be compatible with "dumb" devices like the the RTL units and so there's not a lot of value in special-casing the bladeRF. -Scott On Sun, Sep 22, 2013 at 6:11 PM, Adam Nielsen <a.nielsen@shikadi.net> wrote:
There is also the bladeRF hardware, which is available and in stock. I have a unit and it is a very nice piece of kit. It achieves 40 MS/s @ 12 bit over USB 3.0. It uses a Cypress FX3, so even on USB 2 it should be able to saturate the bus. Unfortunately, the price went way up after their Kickstarter ended. Also, the SW is still in development and not polished yet.
Just to confirm, are you saying you can use the bladeRF as a proper SDR like the RTL devices? I did look at it a while back, but to me it looked like it required all the SDR processing to happen within an onboard FPGA, so I assumed it wasn't a PC-based SDR.
Cheers, Adam.
You are correct that the 2177/78 are not the chip of choice, but SiLABs offers some very interesting choices like the 2158 which does sport an analog output. I should be more careful in my exuberance. http://www.silabs.com/Support%20Documents/TechnicalDocs/Si2158-short.pdf Pictures of a simple effective modification to an EzTV645. This modification made a big improvement in its (noise) performance. http://www.salsburg.com/ezcap/ From: osmocom-sdr-bounces@lists.osmocom.org [mailto:osmocom-sdr-bounces@lists.osmocom.org] On Behalf Of Nick Foster Sent: Saturday, September 21, 2013 6:40 PM To: Jay Salsburg Cc: osmocom-sdr@lists.osmocom.org Subject: RE: new TV Tuner Chip, the Si2177 As others have tried to explain, this chip does not provide an analog output for you to digitize with your soundcard. It turns RF into H.264 digital video. That's all. There's nothing to digitize and no place to plug your soundcard into. --n What is all this talk about USB. High-end Audio Interfaces digitize/quantize at 192KHz/24bit. Since these new Tuners are almost naked on a surface mount board, all that is needed other than a good audio card is a BusPirate to control the I2C to get one of these new Analog TV tuner Chips to work as a SDR. Since most "Intelligence" in radio is narrow band typically a Voice Channel, all that a wideband A/D gives you is a view from 50,000 feet of the spectrum which is OK for Test and Measurement. I cannot use my TV Dongles for most of my (Forward Scatter RADAR) applications because of their low resolution, I must use a conventional Scanner because it converts the signal to Audio. What I need is high definition and narrow band, the current Dongles are typically Wide Band low resolution (2Mhz/8bit). This is why a Tuner Chip with low noise and demodulated analog output is attractive to me, it is a complete solution. -----Original Message----- From: osmocom-sdr-bounces@lists.osmocom.org [mailto:osmocom-sdr-bounces@lists.osmocom.org] On Behalf Of Leif Asbrink Sent: Saturday, September 21, 2013 4:38 PM To: osmocom-sdr@lists.osmocom.org Subject: Re: new TV Tuner Chip, the Si2177 Hi Adam,
The bandwidth of the I/Q pair is too large to be transmitted over USB for the reception of TV signals. After demodulation the bandwidth is lower so it would (marginally) fit an USB interface if we talk about traditional analogue TV. For digital TV the bandwidth reduction by the decoder is much larger.
Is that correct? From what I can find, an analogue TV signal has a bandwidth of around 6-8MHz. Yes.
The HackRF is an SDR that works over USB2.0 and can capture a chunk of RF spectrum up to 20MHz, which should be ample for one analogue (or even digital) TV signal, perhaps even two if the channels are close enough together.
I was under the impression that the USB channel was the reason that the highest sampling rate I was aware of in continous mode is 4 MHz (QS1R) Now, I did not think of the fact that for the dongle we need only 8 bit while normal SDRs use 16 bit so with my assumption the maximum sampling speed would be 8 MHz. To receive 6-8 MHz bandwidth one would need to sample quite a bit higher. Surely one could apply digital filters but even so a, substantial amount of oversampling is needed. Are you sure HackRF really can send 20 MHz of bandwidth over USB 2.0 continously? Where did you find that info? (Seems I should try to push SDR manufacturers who use USB 2.0 to supply modes with higher sampling rates...) 73 Leif ----- No virus found in this message. Checked by AVG - www.avg.com Version: 2013.0.3408 / Virus Database: 3222/6687 - Release Date: 09/21/13 _____ No virus found in this message. Checked by AVG - www.avg.com Version: 2013.0.3408 / Virus Database: 3222/6688 - Release Date: 09/21/13
Are you sure HackRF really can send 20 MHz of bandwidth over USB 2.0 continously? Where did you find that info? (Seems I should try to push SDR manufacturers who use USB 2.0 to supply modes with higher sampling rates...)
I can't find any specific examples now, but most pages discussing the HackRF (including those from people who have a prototype) say there is no problem receiving 20Msps from the device. I find this quite believable, as one of the aims for the project was to be able to monitor a 20MHz wi-fi channel at 5.8GHz, so that the 802.11 protocol could be implemented entirely in software. The only reason the RTL devices are limited to smaller bandwidths seems to be a limitation in the performance of the RTL2832 chip itself - something not entirely surprising to anyone familiar with the performance of other Realtek products ;-) Cheers, Adam.
On Sat, Sep 21, 2013 at 3:43 AM, Leif Asbrink <leif@sm5bsz.com> wrote:
The bandwidth of the I/Q pair is too large to be transmitted over USB for the reception of TV signals.
This is not quite correct claim. See Mirics MSi3101 chipset for example. SG
Digital TV reception is the target App for these new Tuner Chips, the target platform is the Smart Phone. If you read the Preliminary Datasheet, SILICON LABS conspicuously mentions their new Tuner exhibits immunity to interference from Wi-Fi and LTE. Since Smart Phone and Tablet technology is accelerating at WARP speed with a Moore Iteration every few months (not 18 months like he envisioned), it is logical that Technology Convergence in Smart Phones is not over, designers will probably put TV Receivers in Smart Phones and Tablets, and LTE in Set Top Boxes and TVs. I remember, in the 1980s SILICON LABS was the first to produce Multi Op-Amp DIPs, I still have some of them in my Chip Stash. If Memory serves me, their designation was L144. I apologize for substituting terms in the previous messages, it did get some of you going. Not since I was a Wafer Fab Engineer at Western Digital has that annoying practice gotten me in trouble when I openly referred to my Employer as Western Vegetable. -----Original Message----- From: osmocom-sdr-bounces@lists.osmocom.org [mailto:osmocom-sdr-bounces@lists.osmocom.org] On Behalf Of Leif Asbrink Sent: Friday, September 20, 2013 7:43 PM To: osmocom-sdr@lists.osmocom.org Subject: Re: new TV Tuner Chip, the Si2177 The bandwidth of the I/Q pair is too large to be transmitted over USB for the reception of TV signals. After demodulation the bandwidth is lower so it would (marginally) fit an USB interface if we talk about traditional analogue TV. For digital TV the bandwidth reduction by the decoder is much larger. I would not be surprised if the Si Labs chips have an option to send unprocessed I/Q data to the USB. Somebody should approach them and ask:-) 73 Leif / SM5BSZ
OK, for those who do not grasp the principle of On-chip Demodulation, SILICON LABS is manufacturing a spectrum of advanced Tuners, one of which may suit the mindset of those who buck the idea of a Demodulator on chip. There is one that demodulates Analog TV alone, one that demodulates Digital TV alone, and one that does both. Ask yourself this question... Why is there an A/D converter chip on the current Tuner Dongles? Would it not be better to convert the unadulterated demodulated Digital stream directly into a 192k/24bit audio card (or just 48k/16bit)? This new capability tells my Engineering mind that the noise floor would go way down, which is the main deficiency with the current cheap TV Tuner Dongles, keeping them from being used for low level narrowband reception.
http://www.silabs.com/Support%20Documents/TechnicalDocs/Si2157-short.p df
-----Original Message----- From: osmocom-sdr-bounces@lists.osmocom.org [mailto:osmocom-sdr-bounces@lists.osmocom.org] On Behalf Of Jay Salsburg Sent: Thursday, September 19, 2013 12:21 PM To: osmocom-sdr@lists.osmocom.org Subject: new TV Tuner Chip, the Si2177
I just received a Product Announcement from SILICON LABS. There new TV Tuner Chip, the Si2177, appears to be able to demodulate Analog TV directly on the chip without software. If I am not mistaken, this function is a new feature in TV Tuner Chips, which may provide a much better SDR than current TV Tuner Chip Dongles, especially when it comes to noise performance. It also eliminates almost all external components. RF Input Frequency Range - 42 to 870 MHz
Si2177 5th Generation Silicon TV Tuner ICs
http://www.silabs.com/Support%20Documents/TechnicalDocs/Si2177-short.p df
----- No virus found in this message. Checked by AVG - www.avg.com Version: 2013.0.3408 / Virus Database: 3222/6680 - Release Date: 09/19/13
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participants (12)
-
Adam Nielsen -
Ben Wojtowicz -
Gisle Vanem -
Jay Salsburg -
Jürgen Kahrs -
Leif Asbrink -
Nick Foster -
Pete Zaitcev -
Rasz -
Scott Cutler -
Sdr Guru -
Sylvain AZARIAN