Agilent Technologies E1441A user service Burst Count

For all waveforms used with burst, if the carrier frequency is set less than or equal to 100 Hz, the following relationship applies.

Burst Count	≤500 seconds for Carrier ≤100 Ηz
Carrier--------------------------------------------------Frequency

If you attempt to set the carrier frequency to a value that is not valid, the function generator will automatically adjust the frequency to the minimum value allowed with the present burst count. A -221, “Settings conflict” error is generated and the frequency is adjusted.

For the counted burst mode, the sync signal is a TTL “low” while the specified number of cycles is output (for the duration of the burst). After the specified number of cycles has been output, the sync signal goes “high” until the next burst. The sync signal is output from the front-panel SYNC terminal.

For the external gated burst mode, the sync signal is a TTL “high” when the output is positive, relative to zero volts (or the dc offset value). The signal is a TTL “low” when the output is negative, relative to zero volts (or the dc offset value). The sync signal is output from the front-panel SYNC terminal.

Use the following command to set the frequency:

FREQuency <frequency>MINimumMAXimum

You can also use the APPLy command to select the function, frequency, amplitude, and offset of the carrier with a single command. Because the APPLy command also changes duty cycle, modulation type, trigger source, and trigger slope, you must place the APPLy command first in any sequence of configuration commands.

Burst Count The burst count defines the number of cycles to be output per burst. Used only in the "counted" burst mode (internal or external trigger).

Certain combinations of burst count and carrier frequency are not allowed. If you attempt to specify a burst count that is not valid, the function generator will automatically adjust the count to the maximum value allowed with the present carrier frequency.

Make sure you note the restrictions in “Burst Carrier Frequency” before setting the burst count.

Burst count: 1 to 50,000 cycles, in 1 cycle increments. You can also select an infinite burst count. The default is 1 cycle.

When the internal trigger timer is selected (TRIG:SOUR INT), the specified number of cycles is output each time the timed trigger occurs. the repetition rate of the trigger timer is set by BM:INTernal:RATE <freq>.

When an external trigger source is selected

(TRIG:SOUR EXTTTLTRG<n>), the burst count and burst phase remain in effect but the burst rate is ignored. The specified number of cycles is output each time a trigger signal is applied to the selected trigger source. The

38 Agilent E1441A Application Information Chapter 2