new TV Tuner Chip, the Si2177

Leif Asbrink leif at sm5bsz.com
Sat Sep 21 00:43:14 UTC 2013


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 at lists.osmocom.org [mailto:osmocom-sdr-bounces at lists.osmocom.org] On Behalf Of Jay Salsburg
> Sent: Thursday, September 19, 2013 12:21 PM
> To: osmocom-sdr at 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
> 
> 
> 
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