Keysight Technologies 3458A Guide D'utilisation page 207

– When direct-sampling an input signal with a frequency content ≥1 MHz, the
Direct sampling example
The following program is an example of DC-couple direct-sampled digitizing. The
SWEEP command specifies an interval of 30 µs and 200 samples. Level triggering
is set for 250% of the 10 V range (250% of 10 V = 25 V). The samples are sent to
reading memory in DINT format. The samples are then sent to the controller,
converted, and printed. By deleting line 110, samples will be transferred directly
to the controller instead of using reading memory. However, the controller and
GPIB must be able to transfer samples at a rate of at least 134k-bytes/second or
the multimeter will generate the TRIGGER TOO FAST error. Refer to
transfer across GPIB
10OPTION BASE 1!COMPUTER ARRAY NUMBERING STARTS AT 1
20INTEGER Num_samples,I,J,K!CREATE INTEGER VARIABLES
30Num_samples = 200!200 SAMPLES
35ASSIGN @Dvm TO 722!DESIGNATE MULTIMETER ADDRESS
40ASSIGN @Buffer TO BUFFER [4*Num_samples]!SETUP CONTROLLER BUFFER FOR
45!SAMPLES, (4-BYTES/SAMPLE * 200 SAMPLES = 800 BYTES)
50ALLOCATE REAL Samp(1:Num_samples)!CREATE REAL ARRAY FOR SAMPLES
60OUTPUT @Dvm;"PRESET FAST"!DINT FORMATS, TARM SYN, TRIG AUTO
70OUTPUT @Dvm; "SWEEP 30E - 6,200"!30 μs INTERVAL, 200 SAMPLES
80OUTPUT @Dvm; "DSDC 10"!DIRECT-SAMPLING, 10 V RANGE
90OUTPUT @Dvm;"LEVEL 250, DC"!LEVEL TRIGGER AT 250% OF RANGE (25 V)
100OUTPUT @Dvm;TRIG LEVEL"!LEVEL TRIGGER EVENT
110OUTPUT @Dvm; "MEM FIFO"!ENABLE READING MEMORY, FIFO MODE
120TRANSFER @Dvm TO @Buffer;WAIT!TRANSFER SAMPLES TO CONTROLLER
130OUTPUT @Dvm; "ISCALE?"!QUERY SCALE FACTOR FOR DINT FORMAT
140ENTER @Dvm;S!ENTER SCALE FACTOR
150FOR I=1 TO Num_samples
Keysight 3458A User's Guide
first sample may be in error because of interpolator settling time. To ensure the
first sample is accurate, insert a 500 ns delay before the first sample (DELAY
500E-9 command).
in Chapter 4 for more information.
Digitizing 5
High-speed
207