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Unit. In only one case is the Response Message generated when the response is read (as opposed to when the
response is parsed), and this is when querying Arbitrary Waveform data. All other queries generate the Response
Message when they are parsed.
4.5.4 Coupled Commands
Coupled Commands are either commands whose execution validity depends on the value of other parameters, or
commands whose execution changes the value of another parameter. The execution of commands designated as
being coupled is deferred until all other commands in the same Program 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 MODEL 4076 and 4079:
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 (GPIB Only)
Arbitrary waveform values may be sent to the device in one of three formats:
a) ASCII values,
b) Definite form arbitrary data, and
c) Indefinite form arbitrary data.
4.7 Instrument Identification
The *IDN? common query is used to read the instrument's identification string. The string returned is something
similar to the following:
B&K, MODEL 4076,0,V1.40
4.8 Instrument Reset
The *RST common command effects an instrument reset to the factory default power up state.
4.9 Self Test
The *TST common query causes the device to perform a self test. This self test consists of checking the functionality
