sabato 25 gennaio 2020

Real test of "Signal Predator" from Elenos : 16 bit Direct Sampling technology for a real OTT instrument at low cost

The use of Direct Sampling SDR 16 bit technology allows to challenge with Modulation Monitor instruments and Test Sets at a cost in the range of a tens or lower .

All this is possible with the new Signal Predator from Elenos :

At the end of the page you can see the streaming of one Signal Predator working live on the field .

Or you can use this link :

One of the most challenging measurement is the stereo crosstalk of a stereo analog signal .

Just to give you an example a very small  impairment of amplitude response of  +/- 0.07 dB in amplitude and phase of +/- 0.45 ° between 30 Hz and 53 kHz do not allow the stereo crosstalk to be better than 45 dB !

Just check for reference at page 9-10 the document : 

Now also the transmitters tipically use digital generation of the analog FM signal , so I have checked the crosstalk of the stereo signal generated from an Elenos ETG Indium Digital series connecting the RF monitor of the transmitter to the input of the Signal Predator .

The values measured from 30 Hz to 15 kHz was equal or better than 75 dB .

With this values it is hard to say if the limit depends on the transmitter or on the Signal Predator .

This order of magnitude of measurements so far was only possible with huge instruments with very huge costs , only possible to big broadvasting companies , while the cost of a Signal Predator is affordable from many companies and people .

Another measurement of tremendous impact for a Radio Station is the live measurement of the Signal to Noise Ratio in the Audio demodulated signal with NON NEED TO INTERRUPT THE PROGRAM .

This allows to continuously monitoring the quality of all the FM Stations ,  locally or on air .

Signal Predator also display , together with the Stereo Pilot and RDS modulation deviation , the constellation of the RDS BPSK symbols :

I understand now the reason  why the Signal Predator advertising says :


The measurements screens of the Stereo Crostalk are as follow .

The crosstalk between the L & R channels are the difference of the audio carriers between the two white traces  at 30 - 1000 - 5000 - 15000 Hz .