Stanford Research Systems SR780, Operating Manual And Programming Reference

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Example Program 5-117
SR780 Network Signal Analyzer
printf ("\n\nWait for octave settle...");
GetSr780 ("DSPS?"); //clear any sticky bits in the Display status word
//and then wait until the settle bits become set
do { GetSr780 ("DSPS?"); } while ( (atoi(recv)&0x0404) != 0x0404 );
printf ("done\n\n");
TxSr780 ("SVTR 0,5"); //save DisplayA to Trace5
TxSr780 ("RCTR 1,5");
//recall Trace5 to DisplayB
GetSr780 ("DSPN? 1"); nlen = atoi(recv); //query the length of DisplayB
printf ("DisplayB length = %d\n",nlen);
/* ***************************************************** */
/* ****** Download an octave trace ****** */
// Make Trace5 a constant -27 dBVpk for all bins.
// Convert -27 dBVpk to Volts (10^(-27/20))=0.04467
// Trace5 is already defined as an Octave measurement
// so the downloaded points are assumed to be Volts squared!
octreal = 0.04467*0.04467; //(44.67 mV)^2 real part
octimag = 0.0; //no imaginary part
//This section needs to be modified for your GPIB interface
printf ("Loading Trace 5...");
TxGpib (sr780,"TASC? 5,34"); //use TxGpib (no wait for IFC RDY)
//TASC downloads ASCII data,
//use TLOD to download binary data.
transmit("mla talk 10",&status);
//make SR780 a talker, pc a listener
rarray (&ack, 4, &length, &status); //binary read 4 bytes (long int)
//return value should be 1
printf ("%d bytes recvd [val=%ld]...",length,ack);
// TASC (TLOD) replaces the data in an existing Trace (5).
// The Trace measurement and length are not changed!
// Download 34 bins of data (real, imaginary) with commas to separate,
// and EOI at the end.
// First 33 bins are the spectrum, last bin is the Total Power bin.
// All points are complex.
// For an octave measurement, the imaginary parts are all zero.
transmit("mta listen 10",&status); //make SR780 a listener, pc a talker
for (i=0; i<33; i++) { //download 33 octave bins
sprintf (cmd,"DATA '%lf, '", octreal); //real part
transmit (cmd,&status);
sprintf (cmd,"DATA '%lf, '", octimag); //imaginary part
transmit (cmd,&status);
}
// last bin is the total power bin
sprintf (cmd,"DATA '%lf, '", octreal*33); //real part of total power bin
transmit (cmd,&status);
sprintf (cmd,"DATA '%lf' END", 0.0); //imag part of total power bin,
transmit (cmd,&status); //last value, terminate with EOI!
WaitIFC (); //serial poll until IFC set, ok to continue
printf ("done\n");
TxSr780 ("RCTR 1,5");
//recall Trace 5 to DisplayB to view the new data
/* ***************************************************** */
/* ****** Define a User Function ****** */
// define Func1 = Oct(1)/Trace5
TxSr780 ("USRO 1,14,-5,45"); //14=Oct(1), -5=divide, 45=Trace5
TxSr780 ("MEAS 0,25"); //DisplayA measures UserFunc1