In order to quantify my abilty to receive weather satellite images using DVB-T running with GNURadio, I have setup a very simple experiment as follows: * tune a frequency synthesizer to 137 MHz, FM modulation, 5 kHz deviation and 2400 Hz FM frequency * frequency synthesizer output power setup to -91 or -101 dBm (same setting for all receivers, 2 sets of measurements) * connect the output of the synthesizer to the input of the DVB-T (in all cases, a new BNC connector was solder instead of the original 75-ohm antenna connector), * plot the RF signal FFT and the FFT of a WBFM demodulator block as found in GNURadio (always same settings: 30 dB IF gain and 30 dB RF gain) * assess the receiver quality by the signal to noise ratio of the FM output.
Is this a reasonable way of assessing a receiver sensitivity ? Is there some sort of well defined "protocol for assessing a receiver quality for small signal detection ? The results of my measurements are found at http://jmfriedt.free.fr/dvbt-comparison.html => is it reasonable from these graphs to conclude that the FC0013 based receiver is by far the most sensitive, despite the non-linearities visible in the demodulation process ? Thanks, JM -- JM Friedt, FEMTO-ST Time & Frequency/SENSeOR, 32 av. observatoire, 25044 Besancon, France
