HP 8340b - Page 83

SNdt Sweep Number, is used to establish the number of steps for a stepped sweep. The minimum
number of steps is 10, while the maximum number is 1000; the frequency sweep span is divided by
this SN number to determine the step increment. SN initializes the stepped sweep conditions, but
the IF code or the HP-IB statement TRIGGER must be used in conjunction with SN to actually
initiate each frequency step. A BASIC example:
100 OUTPUT 719; "FA8GZ FB12G2 SN400"
110 FOR N = 1 TO 400
120 OUTPUT 719; "IF"
130 NEXT N
This program causes a sweep that starts at 8 GHz and makes 400 steps (19 MHz increments) to
the 12 GHz stop frequency. The IF code in line 120 initiates each of the 400 increments; alter¬
natively, line 120 could be:
120 TRIGGER 719
SPdt Set Power step size, is identical to the SHPL code, and both are equivalent to the [SHIFT]
[POWER LEVEL] key which is described in Figure 3-7.
The power step size can be as small as 0.05 dB, or as large as 50.00 dB. Once set, the power level
can be incremented by the UP code or decremented by the DN code. Here is a BASIC example of
a 120 dB, discrete power sweep at a 12 GHz CW frequency:
100 OUTPUT 719; "CW 12 GZ"
110 OUTPUT 719; "SP 0.05 DB"
120 OUTPUT 719; "PL -110 DB"
130 FOR N = 1 TO 2400
140 OUTPUT 719; "UP"
150 NEXT N
160 GOTO 120
The power sweep starts at —110 dBm, and increments in 2400 discrete, 0.05 dB steps to an end
value of 10 dBm.
SWm SWap network analyzer channels, is used in conjunction with alternate mode and causes the
foreground and background instrument states to be transposed.
Foreground refers to the present operating configuration of the HP 8340B/41B as seen on the
front panel displays and indicators, while background is the configuration that is derived from one
of the SAVE/RECALL registers 1-9. When the HP 8340B/41B is alternating between the fore¬
ground and background configurations only the foreground configuration shows on the front
panel displays and indicators, even when the instrument is operating under background condi¬
tions. Hence, only the foreground configuration can be changed. SW transposes foreground and
background, causing the background to show on the front panel where changes can be made.
Define the foreground configuration as state '‘B” at the moment that alternating operation begins:
At any time thereafter, SW0 causes state “A” to be the front panel state, while SW1 causes state
“B” to be the front panel state.
SW does not change any of the values in the SAVE/RECALL register from which the background
was derived, even if the background values are changed (when alternate mode is initiated the
values in the RECALL register are transferred into the background register; after this transfer,
only the background register is involved in alternating operations).
Tlb(b) Test HP-IB Interface, verifies correct data transmission along the HP-IB interface. The pro¬
cedure involves sending a data byte to the HP 8340B/41B, then having the HP 8340B/41B return
the same byte to the computer where the out-going and incoming data is compared. In BASIC:
3-80
Operating Information
HP 8340B/41B