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Agilent E1441A Application Information 43
Chapter 2
FSKey:SOURce EXTernal
select ext FSK source
TRIGger:SOURce EXT | TTLT<0-7>
now select which ext source
Frequency Sweep In the frequency sweep mode, the function generator “steps” from the start
frequency to the stop frequency at a sweep rate which you specify. You can
sweep up or down in frequency, and with either linear or logarithmic
spacing. You can also configure the function generator to output a single
sweep (one pass from start frequency to stop frequency) by applying an
external trigger. The function generator can produce a frequency sweep for
sine, square, triangle, ramp, or arbitrary waveforms. Topics covered on
frequency sweep are:
• “Sweep Start and Stop Frequencies” on page 43
• “Sweep Time” on page 43
• “Sweep Mode” on page 44
• “Sweep Trigger Source” on page 44
Only one modulation mode can be enabled at a time. When you enable the
sweep mode, the previous modulation mode is turned off.
Use the following command to enable the frequency sweep:To ensure
proper operation, you should enable the sweep mode after you have set up
the other modulation parameters.
SWEep:STATe OFF|ON
Sweep Start and Stop
Frequencies
The start frequency and stop frequency set the upper and lower frequency
bounds for the sweep. The function generator begins at the start frequency,
sweeps to the stop frequency, and then resets back to the start frequency.
Start and Stop frequencies: 10 mHz to 15 MHz (100 kHz for triangle and
ramp). The sweep is phase continuous over the full frequency range. The
default start frequency is 100 Hz. The default stop frequency is 1 kHz. The
*RST command sets the start frequency to 10 mHz (minimum) and the stop
frequency to 15 MHz (maximum).
For arbitrary waveforms, the maximum start or stop frequency depends on
the number of points specified in the waveform. The five built-in arbitrary
waveforms can be output at a maximum of 5 MHz.
To sweep
up in frequency, set the start frequency < stop frequency.
To sweep
down in frequency, set the start frequency > stop frequency.
The sync signal is a
TTL “low” at the start of the sweep (when the start
frequency is output) and is a
TTL “high” at the end of the sweep (when the
stop frequency is output). The signal is output from the front-panel SYNC
terminal.
Use the following command set the start and stop frequencies:
FREQuency:STARt <frequency>|MINimum|MAXimum
FREQuency:STOP <frequency>|MINimum|MAXimum
Sweep Time The sweep time specifies the number of seconds required to sweep from the