UNIMO Technology PZ-400 User Maintenance Manual Download Page 11

Page: 11 / 11

Maintenance Manual

When the channel spacing 12.5

㎑

and 25

㎑

are selected, Q55 and Q56 make the audio sound and the

noise squelch in the same level.

The squelch is adjusted in 10 steps by supplying the noise voltage of

U301 (pin#14) to P2.6 A/D port of MPU (U51).

Summary of Contents for PZ-400

Page 1: ...Maintenance Manual PZ series Portable Radio PZ 400 PZ 100...

Page 2: ...Maintenance Manual 2 TABLE OF CONTENTS FRONT ASSEMBLY 3 Microphone and Speaker 3 REAR ASSEMBLY 3 CIRCUIT ANALYSIS 3 AUDIO LOGIC SECTION 3 R F SECTION 6...

Page 3: ...f Radio and the RF circuitry which decides the communication quality and performance The circuit of sub board consists of battery connectors and fuse for protected the main circuit And the specialized...

Page 4: ...ry nominally 7 5Vdc and fuse F50 provides protection for the main circuit And also the 3 3 volts for Bluetooth module RF section and VCO can be controlled separately by microprocessor Personality EEPR...

Page 5: ...1 handles nearly all the audio functions in the PZ series radio It has the audio filter that operates the basic functions of radio the Limiter the Splatter Filter the Compander and the Scrambler It ca...

Page 6: ...tion consists of the following circuits A frequency synthesizer for generating the transmit carrier frequency and the first mixer injection frequency for the receive circuitry Transmit circuits Receiv...

Page 7: ...136 174 for VHF model When VCO_RX signal is High it turns transistor Q67 on and the RX5V1 5Vdc is supplied to the RX_VCO RX VCO oscillates transmit frequency by C458 C402 C404 C405 L81 D74 The RX VCO...

Page 8: ...0 10Vdc which is control the frequency of the VCO The Voltage converter U52 converts 5Vdc to 10Vdc to provide the necessary voltage range The low pass filter is used for Loop filter circuit to reduce...

Page 9: ...5V2V is supplied to D60 D61 and D62 the diodes will be turn on and the carrier is emitted to Antenna The RX direction is blocked by D62 and it protects the RX part When RX operation TX5V2 will be OFF...

Page 10: ...e 1st IF band pass filter The Crystal filter XF31 selects 1st IF frequency out of frequencies generated from the mixer part The Crystal filter matching circuit consists of L73 C257 C223 C208 and R209...

Page 11: ...the channel spacing 12 5 and 25 are selected Q55 and Q56 make the audio sound and the noise squelch in the same level The squelch is adjusted in 10 steps by supplying the noise voltage of U301 pin 14...