Hi all, I am new to gnu radio, I did look around at different places at the internet but did not really find an answer. I am trying to send data using a GFSK transmitter in a bursted mode (ie :I need to send the “Premable +Synchro + L-field + data +CRC” N times per second). Eventually, my task is to develop a GFSK transmitter based on the following requirements: • Preamble : 55 55 • Synchro : F6 72 • L-field ( data + CRC) : 20 • Data (30 bytes) : FFFFFFFFFFFFFFFFFFFFFFFFFF0110AABBBBBBCE9800010 • CRC : FECB • Modulation : GFSK • Deviation : +/-2,4KHz +0,2% • Modulation index : 2 • Filter index : 0.5 BT • Bitrate : 2400 bit/s • Carrier Frequency : 169.41 Mhz I have designed a transmitter based on gnu radio as follow The main blocs are : • File source block which contain the data to be transmitted, • GFSK Mod block :I choose the number of samples per symbol (sps)= 100, I used the following equation to calculate the sensitivity sensitivity = Pi * modulation Index / sample par symbol and filter index BT= 0.5 • Rotational resampler block: the interpolation = samp_rate * (sps -1) and decimation is equal to my sample_rate • And finally a multiply const block that feeds the USRP sink and Gui FFT and time sinks I am using gnuradio 188.8.131.52, USRP X310 with UBX daughterboard and UHD 003.010. I have visualized my signal with a spectrum analyzer and It looks good ( I hope that what I did was correct ). Now, I am trying to burst my data. In fact, I would like to transmit the “Premable +Synchro + L-field + data +CRC” N times per second. I have tried to use the “PDU to stream” bloc and the unpacked to packed bloc but I was always getting a continuous transmission. Any hint please on how to make data contained in my file bursted ? Best regards.
on 2017-01-12 15:36