User`s manual

Logarithmic
Sweeping
The LOG_SWP program shows you how to select logarithmic spacing
between the frequencies in a frequency sweep. The program sets up a seven
point logarithmic frequency sweep from 1 Hz to 1 MHz. Thus, the swept
frequencies are: 1 Hz, 10 Hz, 100 Hz, 1 kHz, 10 kHz, 100 kHz, 1 MHz.
Using the flowchart in Figure 4-1 as a guide, the steps of this program are:
1. Set the frequency sweep mode
[SOURce:]FREQuency[1]:MODE <mode>
2. Set the start frequency
[SOURce:]FREQuency[1]:STARt <start_freq>
3. Set the stop frequency
[SOURce:]FREQuency[1]:STOP <stop_freq>
4. Set the number of points (frequencies) in the frequency sweep
[SOURce:]SWEep:POINts <number>
5. Set linear or logarithmic spacing
[SOURce:]SWEep:SPACing <mode>
6. Set the number of sweeps
[SOURce:]SWEep:COUNt <number>
7. Set the output function
[SOURce:]FUNCtion[:SHAPe] <shape>
8. Set the signal amplitude
[SOURce:]VOLTage[:LEVel][:IMMediate][:AMPLitude] <amplitude>
9. Place the AFG in the wait-for-arm state
INITiate[:IMMediate]
BASIC Program Example (LOG_SWP)
1 !RE-STORE"LOG_SWP"
2 !This program logarithmically sweeps from 1 Hz to 1 MHz in seven
3 !points.
4 !
10 !Assign I/O path between the computer and E1445A.
20 ASSIGN @Afg TO 70910
30 COM @Afg
40 !
50 !Set up error checking
60 ON INTR 7 CALL Errmsg
70 ENABLE INTR 7;2
80 OUTPUT @Afg;"*CLS"
90 OUTPUT @Afg;"*SRE 32"
100 OUTPUT @Afg;"*ESE 60"
Continued on Next Page
Chapter 4 Sweeping and Frequency-Shift Keying 133