Multiple Units Locking, Arb, Generator

7.9 Multiple Units Locking

7.9.1 Introduction to Multiple Arb Locking

With this feature, users may lock several arbitrary waveform generators together to generate multiple simultaneous signals, which are locked together in frequency. The user may then adjust a phase-offset field to obtain a desired phase relationship between the waveforms with a minimum phase resolution of 0.01 degrees. Any shape of waveform may be used. In fact, waveforms of different shapes may be locked together as long as they all have the same number of points.

Quick Start Guide

To implement Multiple Unit Locking, follow these steps:

1.Cable units together as shown below.

2.Place the Master Unit in Arbitrary Waveform Mode and set the mode on the LCD display to Lock Master

3.Likewise set the mode on each slave unit to Lock Slave

4.Load waveforms into the Master and Slave units. The waveforms may differ in shape but they must each have the same number of points. To generate phase offsets up to 359.99 degrees, the number of points must be either = 32,768 or ≤ 16,384 (refer to the following section “Waveform Size Restrictions”).

5.Set the sampling rate on the Master Unit to the desired sampling frequency. (The frequency shown on the slave units is not used).

6.If desired, set the phase offset on each Slave Unit(s) to the desired phase offset(s).

7.Optionally save the setup on each unit using the Store/Recall button. The waveforms will also be saved.

How it works

Arb wave locking works by using common timing signals for multiple arbitrary waveform generators. To lock multiple generators together, two signals are shared: a sample clock and a reset signal (see the diagram below). The sample clock ensures that the waveform points on all generators are generated at exactly the same rate. The reset signal tells all units to “jump to the first sample point” at the same time. With these two signals, all units are guaranteed to be on the same sample point at the same time. The 4070A uses one arbitrary waveform generator as a “Master” unit that generates the sample clock and reset signal for all of the “Slave” units.

Multi Unit Hookup

Two cables are used to connect on master 4070A to one or more slave units.

NOTE: Observe that one of the connectors for the interconnecting cables is on the Front Panel. You may hook from two to six units together this way.

Master	Slave	Slave
Arb	Arb	Arb
Generator	Generator	Generator

SIG	SYNC	ARB	SIG	Ext Arb	ARB	SIG	Ext Arb	ARB
Out	Out	Sync I/O	Out	Clk In	Sync I/O	Out	Clk In	Sync I/O
(front panel)	(front panel)	(rear panel)	(front panel)	(rear panel)	(rear panel)	(front panel)	(rear panel)	(rear panel)
		Reset Sig						to
								to
	Sample Clock							more
	Sample Clock							units

Waveform	Waveform	Waveform
#1	#2	#3

BK Precision 4070A User Manual Rev.2.2