37
Message have been executed. The coupled commands are then grouped together according to their
functionality, and executed as a group. These groups of coupled commands are defined in the 4075B
series:
a)
The commands to set the amplitude, the offset, and to switch the output on. The output being
switched on is included here in order to prevent possible damage to the equipment being
driven as a result of the amplitude and offset not being executed as intended by the user, due
to an execution error.
b)
The commands to set the function, frequency, the point rate, the wavelength, and the
waveform start address. In ARB function, setting the frequency or the point rate causes the
other to change, keeping the wavelength constant (if it, too, is not specified in the same
program message). If the wavelength is specified as well, the frequency or point rate must
change in accordance with the new value. The validity of the start address is a function of the
wavelength. Please refer to the individual commands for more detail.
The maximum frequency is also dependent upon the waveform, so that changing the waveform
may render the current frequency out of range.
c)
The commands to set modulation, modulation source and the function are inter-related. FM
and FSK are not available for ARB function. External source of modulation can be active for
either FM or AM but not both. FSK and FM cannot be active at the same time.
d)
Sweep start and sweep stop frequencies must be distanced more than the minimum allowed
for sweep to function correctly.
4.6
Block Data
Arbitrary waveform values may be sent to the device in one of three formats:
a)
ASCII values
b)
Definite form arbitrary data
c)
Indefinite form arbitrary data
Essentially we would like to check the execution validity of all the data of a command before
execution. When downloading a long arbitrary waveform, however, it is not possible to check
all the data sent before execution, since this would require excessive amounts of memory. The
following compromise has therefore been reached:
An arbitrary waveform is limited in length only by the amount of waveform memory. Each point
is checked and then written to memory. If an invalid value is detected all subsequent values are
discarded, and an execution error is flagged.
Querying arbitrary waveform data will result in a Response Message containing only as many
points as the user requested.
www.calcert.com
1.800.544.2843
0
5
10
15
20
25
30
