osmocom-sdr

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by outgoing.mit.edu (8.13.8/8.12.4) with ESMTP id w2EJvsmv004135 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NOT) for <osmocom-sdr(a)lists.osmocom.org>; Wed, 14 Mar 2018 15:57:55 -0400 To: osmocom-sdr(a)lists.osmocom.org From: Theodric Young <theodric(a)mit.edu> Subject: Meaning of rtl_fm output values Message-ID: <d96cc71b-6d81-d786-ccd1-708c84eba0ff(a)mit.edu> Date: Wed, 14 Mar 2018 15:57:55 -0400 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFjrPIsWRmVeSWpSXmKPExsUixCmqrHusbmWUwc1tLBb7Jl9hcWD0WHXa I4AxissmJTUnsyy1SN8ugSvjx87tbAX7OSv2bJ/G3sC4lr2LkZNDQsBEYvqcdSxdjFwcQgKL mSQWnj/DCuFcZZSY37eNDcKZxizRv/4YI0iLiICixOTf24FaODjYBNQlJv6zAQkLC2hIrL91 jwXE5hWwkvh96Q0TiM0ioCrxdtsWZhBbVCBGomXJB0aIGkGJkzOfgNUzC5hJzNv8kBnClpfY /nYO8wRG3llIymYhKZuFpGwBI/MqRtmU3Crd3MTMnOLUZN3i5MS8vNQiXRO93MwSvdSU0k2M 4FCS5N/BOKfB+xCjAAejEg+vgdrKKCHWxLLiytxDjJIcTEqivPunrIgS4kvKT6nMSCzOiC8q zUktPsQowcGsJMJ7vxConDclsbIqtSgfJiXNwaIkzutuoh0lJJCeWJKanZpakFoEk5Xh4FCS 4D1cC9QoWJSanlqRlplTgpBm4uAEGc4DNFyuDmR4cUFibnFmOkT+FKMxx5+HL9uYOW68eN3G LMSSl5+XKiXO+x5knABIaUZpHtw0UDq4yHbi3CtGcaDnhHkFQAbyAFMJ3LxXQKuYgFZlblsB sqokESEl1cAYvC/tgHRlS0bd5jnmP/RrNsU/5J6oKV7p8ixCsX/y/3f1+69NufA6bvK/ZD3H 9ONOL50fx7tsVejkM1b7PVkywsPsRnRig7Vbm3R4CnNom/9rs3aJA/Oas4WZ3H7tupb8N8np Qy/bcu5Nib3zr84VOPDxw2mnkitF08Nv2O89u0UxJ+n8wa9KLMUZiYZazEXFiQCH7MfT4gIA AA== X-BeenThere: osmocom-sdr(a)lists.osmocom.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: "Discussion on Osmocom SDR projects \(OsmoSDR, rtl-sdr\)" <osmocom-sdr.lists.osmocom.org> List-Unsubscribe: <https://lists.osmocom.org/mailman/options/osmocom-sdr>, <mailto:osmocom-sdr-request@lists.osmocom.org?subject=unsubscribe> List-Archive: <http://lists.osmocom.org/pipermail/osmocom-sdr/> List-Post: <mailto:osmocom-sdr@lists.osmocom.org> List-Help: <mailto:osmocom-sdr-request@lists.osmocom.org?subject=help> List-Subscribe: <https://lists.osmocom.org/mailman/listinfo/osmocom-sdr>, <mailto:osmocom-sdr-request@lists.osmocom.org?subject=subscribe> X-List-Received-Date: Wed, 14 Mar 2018 19:57:59 -0000 Hi, I'm new to SDR and I have a question about the data values that are generated by the rtl_fm program. I got rtl_fm running on my system (cygwin running on Windows 7). It is sending a stream of 16-bit signed integer values to stdout which I can redirect to a file or pipe to an audio playback system, such as sox. So when I do this: rtl_fm -f 88.1M -M wbfm -s 240k -r120k -g 30 | play -t raw -r 120k -b 16 -c 1 -e s -V1 - I hear sweet, sweet music! Hurray! But how do these 16-bit integers relate to the modulation level of the carrier? I'm assuming that the values are directly proportional to the instantaneous frequency deviation of the transmitted signal. Is that right? If so, how do I determine that ratio? I'm hoping to use this to build a device that shows total modulation (as a percentage of the maximum modulation of +/- 75kHz) for an FM radio station. Also, I'm assuming that the sample-rate of the output data stream needs to be at least 120kHz because the baseband signal includes the stereo pilot (19kHz), the stereo subcarrier (38kHz) and an RBDS subcarrier (57 kHz). Any insight would be appreciated. Thanks in advance, Theodric Young

7 years, 3 months

antenna enquiry/long praise inc

by mary

7 years, 3 months

drop in replacement for nonfunctioning "discover_netsdr"

by dale ranta

The module “discover_netsdr” in “rfspace_source_c.cc” failed everywhere that I tried it, except for MacOS 10.6. Here is a drop in replacement that was tested and found to work on 10.6, 10.11, 10.12, 10.13 and ubuntu 16.04 LTS. #include <net/if.h> #include <ifaddrs.h> class interfaceInformation{ public: std::string name; std::string address; std::string broadcast; }; std::vector<interfaceInformation> interfaceList(); static std::vector < unit_t > discover_netsdr() { std::vector < unit_t > units; std::vector<interfaceInformation> list=interfaceList(); for(int pass=0;pass<2;++pass){ for(size_t n=0;n<list.size();++n){ if(pass == 1){ list[n].broadcast="255.255.255.255"; } //std::cout << "name " << list[n].name << std::endl; //std::cout << "address " << list[n].address << std::endl; //std::cout << "broadcast " << list[n].broadcast << std::endl; int sockTx; int sockRx; if ( (sockTx = socket(AF_INET, SOCK_DGRAM, 0)) < 0 ) continue; if ( (sockRx = socket(AF_INET, SOCK_DGRAM, 0)) < 0 ){ close(sockTx); continue; } int sockoptval = 1; setsockopt(sockTx, SOL_SOCKET, SO_REUSEADDR, &sockoptval, sizeof(int)); sockoptval = 1; setsockopt(sockTx, SOL_SOCKET, SO_BROADCAST, &sockoptval, sizeof(int)); struct sockaddr_in host_sa; /* local address */ struct sockaddr_in peer_sa; /* remote address */ struct sockaddr_in peer_sa2; /* remote address */ /* fill in the server's address and data */ memset((char*)&peer_sa, 0, sizeof(peer_sa)); peer_sa.sin_family = AF_INET; peer_sa.sin_addr.s_addr = htonl(inet_network(list[n].address.c_str())); peer_sa.sin_port = htons(DISCOVER_SERVER_PORT); /* fill in the server's address and data */ memset((char*)&peer_sa2, 0, sizeof(peer_sa2)); peer_sa2.sin_family = AF_INET; peer_sa2.sin_addr.s_addr = htonl(inet_network(list[n].broadcast.c_str())); peer_sa2.sin_port = htons(DISCOVER_SERVER_PORT); /* fill in the hosts's address and data */ memset(&host_sa, 0, sizeof(host_sa)); host_sa.sin_family = AF_INET; host_sa.sin_addr.s_addr = htonl(INADDR_ANY); host_sa.sin_port = htons(DISCOVER_CLIENT_PORT); if ( bind(sockTx, (struct sockaddr *)&peer_sa, sizeof(peer_sa)) < 0 ) { close(sockTx); close(sockRx); continue; } if ( bind(sockRx, (struct sockaddr *)&host_sa, sizeof(host_sa)) < 0 ) { perror("binding datagram sock2"); printf("errno %d DISCOVER_SERVER_PORT %d\n",errno,DISCOVER_SERVER_PORT); close(sockTx); close(sockRx); continue; } struct timeval tv; tv.tv_sec = 0; tv.tv_usec = 100000; if ( setsockopt(sockRx, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)) < 0 ) { close(sockRx); close(sockTx); continue; } discover_common_msg_t tx_msg; memset( (void *)&tx_msg, 0, sizeof(discover_common_msg_t) ); tx_msg.length[0] = sizeof(discover_common_msg_t); tx_msg.length[1] = sizeof(discover_common_msg_t) >> 8; tx_msg.key[0] = KEY0; tx_msg.key[1] = KEY1; tx_msg.op = MSG_REQ; sendto(sockTx, &tx_msg, sizeof(tx_msg), 0, (struct sockaddr *)&peer_sa, sizeof(peer_sa)); sendto(sockTx, &tx_msg, sizeof(tx_msg), 0, (struct sockaddr *)&peer_sa2, sizeof(peer_sa2)); while ( 1 ) { size_t rx_bytes = 0; unsigned char data[1024*2]; socklen_t addrlen = sizeof(host_sa); /* length of addresses */ int nbytes = recvfrom(sockRx, data, sizeof(data), 0, (struct sockaddr *)&host_sa, &addrlen); if ( nbytes <= 0 ) break; rx_bytes = nbytes; if ( rx_bytes >= sizeof(discover_common_msg_t) ) { discover_common_msg_t *rx_msg = (discover_common_msg_t *)data; if ( KEY0 == rx_msg->key[0] && KEY1 == rx_msg->key[1] && MSG_RESP == rx_msg->op ) { void *temp = rx_msg->port; uint16_t port = *((uint16_t *)temp); std::stringstream buffer; buffer << int(rx_msg->ipaddr[3]) << "." << int(rx_msg->ipaddr[2]) << "." << int(rx_msg->ipaddr[1]) << "." << int(rx_msg->ipaddr[0]); std::string addr=buffer.str(); //std::cout << "addr " << addr << std::endl; unit_t unit; unit.name = rx_msg->name; unit.sn = rx_msg->sn; unit.addr = addr; unit.port = port; units.push_back( unit ); } } } close(sockTx); close(sockRx); } } return units; } std::vector<interfaceInformation> interfaceList() { std::vector<interfaceInformation> list; interfaceInformation c1; struct ifaddrs *addrs,*iloop; char buf[64],buf2[64]; struct sockaddr_in *s4; getifaddrs(&addrs); for (iloop = addrs; iloop != NULL; iloop = iloop->ifa_next) { s4 = (struct sockaddr_in *)(iloop->ifa_addr); buf[0]=0; if(s4){ inet_ntop(iloop->ifa_addr->sa_family, (void *)&(s4->sin_addr), buf, sizeof(buf)); }else{ continue; } s4 = (struct sockaddr_in *)(iloop->ifa_dstaddr); buf2[0]=0; if(s4){ inet_ntop(iloop->ifa_dstaddr->sa_family, (void *)&(s4->sin_addr), buf2, sizeof(buf2)); }else{ continue; } if(!(iloop->ifa_flags & IFF_UP) || !(iloop->ifa_flags & IFF_BROADCAST))continue; c1.name = iloop->ifa_name; c1.address = buf; c1.broadcast = buf2; list.push_back(c1); } freeifaddrs(addrs); return list; }

7 years, 3 months

RTL-SDR sample bit depth

by John Ackermann N8UR

Hi -- I'm trying to understand the sampling and decimation structure of the RTL-SDR dongle, to work out the effective number of bits after decimation. From Google and looking at the librtlsdr code (which is beyond my programming depth), I think I've figured out the following. I'd much appreciate verification/correction/amplification. 1. Actual ADC in the RTL-2832U is a single-bit sigma-delta running at some very high rate. 2. This is converted to 28.8 msps at 8 bit depth. 3. 28.8 msps is downsampled to the rate requested by the user and sent over the USB bus as 8 bit unsigned IQ pairs. Based on that, I *think*: a. Any processing gain in the downsample from 28.8 msps/8 bits within the chip is lost because the wire samples are limited to 8 bits. The output is 8 bits dynamic range regardless of the sample rate set. b. THEREFORE... for best dynamic range one wants to set the RTL-2832U to the highest sample rate that avoids lost samples, and do further decimation in the host processor, where the added bits aren't lost on the wire. I'd appreciate any verification or correction of that analysis. Thanks, John

7 years, 3 months

Is this compatible for AIS Receiver ?

by Irsyad Irsyad

Sent from my iPhone

7 years, 4 months

RTL-SDR : No supported tuner found

by Lidoro

Hello, I try to install rtl-sdr and gnuradio on my computer, on Linux mint 18.1 cinnamon 3.2.7 64 bits. the installation is going well but when I try to execute rtl_test : Found 1 device(s): 0: Realtek, RTL2838UHIDIR, SN: 00000001 Using device 0: Generic RTL2832U OEM No supported tuner found Enabled direct sampling mode, input 1 Supported gain values (1): 0.0 Sampling at 2048000 S/s. I try intallling with a script and with pybombs, i have the same issue. My dongle have RTL2832 chip and FC0012 tuner it works on windows, and it works when i use "linux live gnuradio dvd". And it works if I start on "linux live gnuradio dvd" and reboot after on linux mint. Thank you for your help Best Regards Lidoro

7 years, 4 months

rtl-sdr with bias T

by Cinaed Simson

Hi - there appears to be problem with rtl-sdr with bias T and the RTL2832U OEM Rafael Micro R820T tuner. I get PLL errors when I try to calibrate it using kal - or when I use rtl_test. Using device 0: Generic RTL2832U OEM Found Rafael Micro R820T tuner Exact sample rate is: 270833.002142 Hz [R82XX] PLL not locked! Setting gain: 33.8 dB And I get the same error PLL when I run rtl_test. If I back out of the latest git version to v0.5.3 it works correctly - I can calibrate the dongle using kal and run rtl_test without any PLL errors. This is a known problem? -- Cinaed

7 years, 4 months

osmosdr::device::find fails to find Rfspace NetSDR on MacOS Sierra

by dale ranta

When I updated to MacOS Sierra osmosdr::device::find stopped finding my NetSDR. This short program shows the problem - ************************************************ fprintf(stderr,"I am here\n"); osmosdr::devices_t devs = osmosdr::device::find(); for(int k=0;k<devs.size();++k){ std::cerr << " k " << k << " "<< devs[k].to_string() << std::endl; } fprintf(stderr,"I am done 2\n"); src = osmosdr::source::make("rfspace=192.168.1.7:50000"); fprintf(stderr,"I am done 3\n"); Output- I am here sdrplay=0,label='SDRplay RSP2 1707039B20' k 0 label='Realtek RTL2838UHIDIR SN: 00000001',rtl=0 k 1 label='SDRplay RSP2 1707039B20',sdrplay=0 k 2 hackrf,label='HackRF HackRF One' k 3 label='RFSPACE SDR-IQ Receiver',sdr-iq=/dev/ttyUSB0 k 4 label='RFSPACE SDR-IP Receiver',sdr-ip=127.0.0.1:50000 k 5 label='RFSPACE NetSDR Receiver',netsdr=127.0.0.1:50000 k 6 cloudiq=127.0.0.1:50000,label='RFSPACE Cloud-IQ Receiver' k 7 driver=sdrplay,label='SDRplay Dev0 RSP2 1707039B20',soapy=0 k 8 label='RTL-SDR Spectrum Server',rtl_tcp=localhost:1234 k 9 label='Red Pitaya Transceiver Server',redpitaya=192.168.1.100:1001 k 10 file=/path/to/your/file,freq=100e6,label='Complex Sampled (IQ) File',rate=1e6,repeat=true,throttle=true I am done 2 gr-osmosdr v0.1.4-136-g49fb5538 (0.1.5git) gnuradio 3.7.11 built-in source types: file fcd rtl rtl_tcp sdrplay hackrf bladerf rfspace airspy soapy redpitaya Using RFSPACE NetSDR SN NS000448 option --DRS BOOT 107 FW 112 HW 100 FPGA 1/7 I am done 3 *********************************************** The device::find routine locates the three other SDRs that I have plugged in, but not the netSDR. The source::make routine however finds it without problem. Looking at the search routines, they are similar to the old ones in CuteSDR. Early last year the CuteSDR routines were revised and now work correctly to find the RFspace NetSDR on Sierra and High Sierra. Dale

7 years, 4 months

osmosdr::device::find fails to find Rfspace NetSDR on MacOS Sierra

by dale ranta

7 years, 4 months

[PATCH] RTL-SDR: Fix regression in FC00012 tuner startup (needs testing on FC2580)

by David Basden

This patch fixes a regression of rtl-sdr dongles with the FC00012 tuner. The code to switch on the FC00012 tuner by pulling it's ~RESET line low ended up with an off-by-one error in a refactor a long time ago, The FC00012 only continued to work by accident as a different bug in rtlsdr_set_gpio_output had a side-effect of pulling low the FC00012's ~RESET line When the rtl_set_gpio_output bug was fixed in ba64a7459a43 the side- effect also went away, leaving the FC00012 tuner in reset, and failing to be detected (or indeed work at all). This patch fixes the original off-by-one error. It's been tested on an FC00012 in a GTek T803 from both warm and cold starts, but needs testing on the FC2580 as both the FC00012 and FC2580 are brought out of reset by a GPIO off the RTL (at least in some designs). If the FC2580 actually uses a different pin, this code will also break. (I'm only going from vague memory that the FC2580 used the same pin.) --- src/librtlsdr.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/src/librtlsdr.c b/src/librtlsdr.c index b369a5d..678fadd 100644 --- a/src/librtlsdr.c +++ b/src/librtlsdr.c @@ -1565,11 +1565,11 @@ int rtlsdr_open(rtlsdr_dev_t **out_dev, uint32_t index) } /* initialise GPIOs */ - rtlsdr_set_gpio_output(dev, 5); + rtlsdr_set_gpio_output(dev, 4); /* reset tuner before probing */ - rtlsdr_set_gpio_bit(dev, 5, 1); - rtlsdr_set_gpio_bit(dev, 5, 0); + rtlsdr_set_gpio_bit(dev, 4, 1); + rtlsdr_set_gpio_bit(dev, 4, 0); reg = rtlsdr_i2c_read_reg(dev, FC2580_I2C_ADDR, FC2580_CHECK_ADDR); if ((reg & 0x7f) == FC2580_CHECK_VAL) { @@ -1581,7 +1581,7 @@ int rtlsdr_open(rtlsdr_dev_t **out_dev, uint32_t index) reg = rtlsdr_i2c_read_reg(dev, FC0012_I2C_ADDR, FC0012_CHECK_ADDR); if (reg == FC0012_CHECK_VAL) { fprintf(stderr, "Found Fitipower FC0012 tuner\n"); - rtlsdr_set_gpio_output(dev, 6); + rtlsdr_set_gpio_output(dev, 5); dev->tuner_type = RTLSDR_TUNER_FC0012; goto found; } -- 2.13.2

7 years, 4 months

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