Tektronix 071-0590-00 Selecting a Pattern, Recalling the Default Setup, Locking the Front Panel

Reference

Recalling the Default Setup

The default setup of the Generator and Analyzer are shown in the Appendix. To return the Generator or Analyzer to this setup, use the following procedure:

1.Turn instrument power off.

2.While holding down the VIEW ANGLE, MSB 1, and (PATTERN) CLEAR keys simultaneously, turn instrument power back on.

3.After you see the message Default Settings appear in the display, release the three keys. In a few seconds the normal display format will appear and the instrument will be in its default setup.

Locking the Front Panel

The instrument's front panel may be "locked" or "unlocked" using the PANEL LOCK control. When the front panel is locked, all keys that can cause a setup change are disabled. It is often useful to lock the front panel during a long or critical test to prevent accidental loss of test results. Note that the LED in the PANEL LOCK control indicates whether the front panel is locked (LED on) or unlocked (LED off).

Simply press the PANEL LOCK control to toggle between the locked (LED on) and unlocked (LED off) state.

Selecting a Pattern

The following section defines the patterns that can be generated and analyzed by the GB1400 and how to set up the Generator and Analyzer to use a particular pattern. Note that the Generator and Analyzer are compatible with the same suite of test patterns and use the same setup procedures.

Pattern Definitions

The GB1400 can generate and analyze Pseudo-random bit sequence (PRBS) and WORD test patterns. Each type has its own set of advantages and uses.

PRBS Patterns

Pseudo-random bit sequence (PRBS) patterns are designed to simulate "live traffic" and have been standardized by the telecommunications and computer industries. As a result they are often used to characterize or qualify new devices or systems. Two key characteristics of a PRBS are its overall length in bits and maximum number of contiguous 0s. The length of a PRBS pattern has the form

2n-1. For example a 223-1 PRBS contains 8,388,607 bits. The maximum number of contiguous 0s in a PRBS pattern is n-1, for example 22 in a 223-1 PRBS.

3-2 GB1400 User Manual