User`s manual
Comments • To simplify the program, SCPI commands are included to select the
reference oscillator, the DDS subsystem, and to start the waveform.
This requires that the only registers written to be the Phase
Increment and Frequency Load Strobe Registers. This program
executes as intended when the SCPI commands in subprogram
Output_function are executed before the registers are written to.
• The subprogram Output_function sets the initial reference oscillator
frequency to 42.94967296 MHz. If a different reference oscillator
frequency is used (that is, 40 MHz or an externally supplied
oscillator), specify that frequency when the Freq_change subprogram
is called (line 200).
• If frequency doubling is in effect (SOUR:FREQ1:RANG command in
subprogram Output_function), the doubled frequency can be changed to
another doubled frequency by passing a number other than 0 as the
fourth parameter to the Freq_change subprogram (line 200).
• Note the following when specifying the number of waveform points
(Npts value passed to the Freq_change subprogram): sine waves and
arbitrary waveforms, Npts = 1; square waves, Npts = 4; ramp and
triangle waves, Npts =
RAMP:POINts value.
Visual BASIC and
Visual C/C++ Program
Versions
The Visual BASIC example program, FREQ1REG.FRM, is in directory
“ VBPROG” and the Visual C example program, FREQ1REG.C, is in
directory “VCPROG” on the CD that came with your Agilent E1445A.
Appendix C Register-Based Programming 491