Tektronix 071-0590-00 Pecl Option for GB1400 Tx, ECL Levels Pecl Levels, Display Setting

Functional Overview

PECL Option for GB1400 Tx

The PECL option is available for the GB1400 Tx only. The PECL option for the GB1400 Tx is a modification that allows for an increased OFFSET RANGE for the clock and data outputs, so that the user will be able to generate PECL levels for testing in a PECL environment. PECL is defined as ECL operating +5.0 V above ground.

Example:

ECL Levels	PECL Levels
VOH ≈ -.9V	VOH ≈ +4.1V
VOL ≈ -1.8V	VOL ≈ +3.2V
VBB ≈ -1.35V	VBB ≈ +3.65V
VTT ≈ -2.0V	VTT ≈ +3.0V

The GB1400 front panel displays, the clock and data amplitude and offset based on a load of 50 Ohms to ground.

The inverted output circuit is identical to the true output circuit.

In the PECL system, Vtt = +3.0V, therefore, the resulting GB1400 Tx signal will be shifted by +1.5V. To get PECL levels at the GB1400 Tx output, set the unit levels as follows:

Display Setting

Resulting PECL Levels (50 Ohms to +3.0V)

AMP = .90V

OFFSET = +1.7V

VOH ≈ +4.10V

VOL ≈ +3.20V

GB1400 User Manual 2-29