OPERATION
3-1-69
Frequency hopping
Carrier frequency hopping is a GPIB operation where the instrument can be instructed to
hop between any of the frequencies contained in the carrier frequency stores and a sequence of
up to 1024 hops may be entered. The time interval between hops can also be entered .
Before executing a carrier hopping sequence, the frequencies must be loaded into the
carrier frequency stores (0 - 99). This can be achieved via the GPIB using the following
commands -
CFRQ
<
frequency value >
STO:CFRQ
< store number
>
To enter the frequency hopping mode, enter the following GPIB commands -
IMODE SWEEPER
SWEEP:TYPE HOP
This will cause the screen as shown in Fig. 3-1-59 to appear on the signal generator -
Fig. 3-1-59 Frequency hopping menu
To load in a sequence, the following command is used -
HOPSEQ
<n0>,<n1>,<n2>,<n3>,<n4>.....
where <n0> - <n> are numeric values in the range 0-99 corresponding to the carrier
frequency store at which the necessary frequency is stored. The hopping sequence length is
determined by the amount of numbers entered.
The other parameter that can be set to control the hopping sequence is the time between
steps. This is done using the command -
SWEEP:HOP:TIME
< t >
where t represents the number of milliseconds.
The 100 frequencies are precalculated and loaded into a software sweep table using the
GPIB command -
SWEEP:CALC
REMOTE
Go To
Local
Sweep Status: WAITING FOR TRIGGER
Sweep Mode: INTERNAL SINGLE
Sweep Type: CARRIER HOPPING
Step Time:
ms
50
C0067
GPIB OPERATION ONLY !!!
