Specifications

5/9/13 888-2857-001 4-1

WARNING: Disconnect primary power prior to servicing.

Platinum VAX-C Series

Section 4

Theory of

Operation

4.1 Introduction

This section contains detailed descriptions of the VAX-C Series transmitter, its internal

sub-assemblies and any pertinent information regarding external assemblies.

This chapter contains four sections:

• Introduction

• Logic Symbols

• Block Diagrams

• Modulator Overview

4.2 Active Logic Symbols

Each logic signal has an active and inactive state and a unique name within the system.

To differentiate between active high or active low logic states on the schematics, a

forward slash (/) is placed in front of an active LOW signal name such as /RF_MUTE.

This means that if this logic line is pulled low, the transmitter RF will be muted. By the

same logic, the signal RF_MUTE_LED (an active high signal with no forward slash)

will turn on the RF mute LED when it goes high.

In some cases, a logic signal may act as a toggle with both states active, as with the

signal /ON_OFF, where LOW = ON and a HIGH = OFF. If this signal is inverted it

would be ON_/OFF.