User`s manual

ECLTrg0 or 1 (the VXIbus ECL trigger lines)

HOLD (suspends sample generation)

TTLTrg0 through 7 (the VXIbus TTL trigger lines)

DDS Frequency

Generator Ranges

The [SOURce:]FREQuency[1]:RANGe command selects frequency doubling of

the DDS frequency generator for the SQUare, TRIangle, and RAMP functions.

This command is only used with DDS (frequency1) frequency generator.

The lower frequency setting (that is, normal setting) for the SQUare

function is determined by:

• Reference Oscillator frequency / 16

The high frequency setting for the SQUare function is determined by:

• Reference Oscillator frequency / 8

The lower frequency setting (that is, normal setting) for the TRIangle and

RAMP functions is determined by:

• Reference Oscillator frequency / 4 / number of points

The doubled frequency setting for the TRIangle and RAMP functions is

determined by:

• Reference Oscillator frequency / 2 / number of points

The doubled setting worsens the frequency resolution by a factor of two and

introduces some sample rate jitter.

Number of Points

versus Frequency

The number of points ([SOURce:]RAMP:POINts) determine the maximum

frequency of the TRIangle and RAMP functions. The more points results in

a lower maximum frequency, but with a better waveform shape. The fewer

points results in a higher maximum frequency, but with lower resolution.

Output Load

Comments

• For correct output amplitude values, the load applied to the AFG

"Output 50/75

Ω" output terminals must be the same value as the

selected AFG output impedance value.

• To output to an open circuit, execute OUTPut[1]:LOAD INFinity or

9.9E+37 (this sets the auto load value off). The Agilent E1445A

then outputs the correct amplitude and offset for an open circuit. The

amplitude and offset range are doubled while resolution worsens by a

factor of 2.

Chapter 2 Generating Standard Waveforms 79