Specifications

User Manual 301/302

and select Sequenced output.

NOTE

The sequence generator goes through its steps in ascending order. In

continuous mode, the sequence is repeated automatically after

completing the last step. In Triggered mode, the output stops at the

last point of the last waveform. In Gated mode, the sequence is

always completed after the gate stop signal.

Adjusting Phase

Offset Between

Channels

The prime purpose of channel synchronization is to control the start

phase in such a way that all channels start generating waveforms at

the same instance, regardless of their respective waveform shape and

frequency.

In general the initial start phase offset is around 0°. However, due to

variations in circuit design and propagation delays, there is an

unavoidable (but minimal) skew between the channels. The initial

skew between channels is specified in Appendix A.

There are no internal provisions to correct skew between channels

however, it can be easily corrected by adjusting the length of the

cables that are connected to the output connectors. One meter of 50Ω

coax cable amounts to about 2 ns of delay time. Use this general

guideline to adjust the skew for your system. For example, if channel 2

lags 1.2 ns after channel 3, you have to delay the output of channel 3

by 1.2 ns. You’ll have to extend the cable for channel 3 by roughly 0.6

meter to compensate for this skew.

Phase offsets are always referenced to channel A. Therefore, you can

program phase offsets for channels B only. An attempt to program

channel A with this parameter will result in an error message.

There are two ways to program phase offsets: 1) Using an angle and

2) Using waveform points. If you use angles to program your phase

offset, you should first compute the equation given in Appendix A to

determine your phase resolution and error. Using waveform points to

specify phase offset is much easier because you have full control over

waveform length and can easily determine the phase offset from the

number of waveform points offset.

TIP

Phase offset between channels is programmable with resolution o

1 waveform point. The more points you have for your waveform, the

better the phase offset resolution you can have. For example, for a

1,000-point waveform, your resolution is 1 / 1000 x 360 = 0.36°; for a

Configuring the Instrument