User Guide

After Sales
Technical Documentation
Compact Handsfree Unit PHF–2
Page 10 Original, 11/94
Functional Description
Figure 1: Block Diagram
MICROPHONE
AMPLIFIER
HANDSFREE
THERMAL
PROTECTION
AUDIO REGULATOR
SWITCHED MODE
POWER SUPPLY
POWER SUPPLY
HANDSFREE
LOUDSPEAKER
AMPLIFIER
Circuit Description
Input Circuit
The input circuit contains the following components:
– C1 – EMI capacitor
– F1 – foil fuse
– L1 / L2 – EMI suppressor chokes
– V1 – voltage suppressor diode (zener type)