HYT RPU416A User Manual

CONTENTS

General 2

Mode Com bination

RPU416A Circuit Description

RPU416A Software Description

RPU416A Parts List

RPU416A Adjust Description

Disassembly fo r Repai r

Exploded View

Packing

RPU416A PC Board View

RPU416A Block Diagram

RPU416A Level Diagram

RPU416A Schematic Diagram

Main T echn i cal Specif ic atio ns

General

This manual is intended for use by experie nced technicia ns familiar w ith similar t ypes of commercial grade communications equipment. It contains main required service information and data for the equipment.

The followi ng preca utio ns are recommended f or per s onal safety: ! DO NOT transmit until all RF connectors are verified secure and any open connectors are

properly ter minated.

! SHUT OFF and DO NOT operate this equipme nt near electrical bl asting caps or in an explos ive

atmosphere.

! This equipment sho uld be maintai ned by qualified technicia ns only.

Mode Combination

1. Mode

User mode: Turn on the power to enter. PC mode"Set and adjust w ith PC softw ar e or programmer.

2. Parts descr iption:

(1) Antenna (2) Channel (f r equency) selector knob

Turn the knob to choose channel from 1~16( channel 16 may be set by distr ibutor as sc an channel).

(3) LED light

Lights red w hile trans mitting, green while recei ving a signal. Flashes red w hen t he bat ter y voltage is low while trans mit ti ng.

(4) Power switch/ Volume control

Turn the knob clockwise to sw itch the transceiver ON, anti-clockw ise to turn off the power till there is a “click” sound, rotate to adjust the volume level.

(5) Speaker (6) Microphone (7) PTT switch (push to talk)

Press the button while transmitt ing, and release it while receiving.

(8) Monitor key

Press it to shut off squelch, noise could be heard, release to connect squelch.

(9) Speaker/microphone jack (10 ) Belt clip (11) Battery (TB-82)

RPU416A Circuit Description

1. Frequency conf igurat io n

The receiver utili zes double co nversio n. The first IF is 38.85M Hz and the second IF is 450kHz. The first

local oscillator sig nal is supplied from the PLL circ uit.

The PLL circuit in the transmitter generat es t he necessary frequencies. Fig.1 s hows t he frequencies. RPU416A frequency ra nge: 450MHz—470MHz

ANT

ANTSW

450KHz

MCF

AMP AMP

38.85MHz

SYSTEM

multiply

TCXO 12.8MHz

AMP

VCO

MICPLL AMP

MIC

Fig.1 F requency conf iguration

2. Receiver

The receiver is double co nversio n superheterody ne.

1) Front - end RF amplifier

An incoming signal from the antenna is applied to a Preamplifier (Q203) after passing through a transmit/ receive switch circuit ( K102 and D103 are off) and a 3-pole LC filter. After t he signal is a mplified (Q203) , the signal is filtered by a band pass filter (a3- pole LC filter ) t o eliminate unwanted signals bef or e it is passed to the first mixer. The voltages of t hese diodes are control led by t o track the MPU. (See Fig. 2- b)

ANT

CF200

D102 D103

APC

IC403 MCU

TUNE

BPF

L208-L211

RF AMP

Q203

BPF

L214.L203.L204

MIXER

Q202

1st Local OSC

(PLL)

MCF

XF200

TCXO

IF AMP

Q201

IF.MIX IC200

multiply

AF AMP LPF.HPF

IC300

WIDE/NARROW SW Q303

AF PA AMP

IC302

Fig. 2 Receiver s ection confi guration

2) First mixer

The signal from the RF amplifier is heterodyned with the first local oscillator signal from the PLL frequency synthesizer circuit at the first mixer (Q202) to creat e a 38.85 MHz first intermediat e frequency (1st IF) signal. The first IF signal is then fed through two monolithic crystal filters (MCFs: XF200) to further remove spurio us signals.

3) IF a mplif ie r

The first IF signal is amplified by Q201, and the n enters IC 200 (FM processing IC). The signal is

heterodyned again with a second local oscillator signal within IC200 to create a 450kHz second IF

RPU416A Circuit Description

signal. The second IF signal is then fed through a 450kHz ceramic filter (CF200) to further eliminate unwanted

4) AF

The recovered AF signal obtai ned from IC200 is amplified by I C300 (1/4), filtered by the I C300 low-pass filter (2/4) and IC300 high-pass filter (3/4) and (4/4), and de-emphasized by R303 and C306. The AF signal is then passed through a WIDE/NARROW switc h ( Q 303) . The processed AF signal passes t hro ugh an AF volume control and is amplified to a sufficient level to drive a loud speaker by an AF pow er amplifier (IC302).

5) Squelch

Part of the AF signal from the IC enter s the FM IC agai n, and t he noise c ompone nt is amplif ied and rectif ied by a filter and an amplifier to produce a DC voltage corresponding to the noise level.

The DC signal from the FM IC goes t o the ana log por t of the microprocessor (I C403). IC403 deter mines whether to output sounds fr om the speaker, IC403 sends a high sig nal to the MUTE and AFCO lines and turns IC302 on through Q302, Q304, Q305, Q306 and Q307. (See Fig.3)

signals befor e it is amplified and FM det ected in IC200.

amplifier

FM IF IC200

IF AMP DET

DET HPF

AMP

IC 300

AF AMP LPF HPF

Q302SWIC302

AF/PF AMP

Q307

Q304.Q305.Q306 SW

IC301

LPF

IC403 MPU

MUTE

AFCO

562676

Q303 W/N SW

BUSY

Fig. 3. AF Amplifier and squelch

6) Receiving signaling

QT/DQT

300 Hz and higher audio frequencies of the output signal from IF IC are cut by a low-pass filter (I C301). The resulting signal enters the microprocessor (IC403). IC403 determines whether the QT or DQT matches the preset value, a nd controls t he M UTE and AFCO and t he s peaker o utp ut sounds according to t he s quel ch r esults.

3. PLL frequency synthesizer

The PLL circuit generates the first local oscillat or signal for r ec ept ion and the RF signal for tr ansmission.

1) PLL

The frequency step of t he PLL circuit is 5 or 6.25kHz. A 12.8MHz reference oscillator s ignal is divided at IC1 by a fixed counter to produce the 5 or 6.25kHz reference fr equency. The voltage controlled oscil lator (VCO) output signal is buffer amplified by Q 6, then divided in IC1 by a dual-mod ule

RPU416A Circuit Description

programmable counter. The divided signal is compared i n phase with the 5 or 6.25kHz reference signal in the phase comparator i n IC1. The output signal from the phase comparator is filter ed t hrough a low- pass filter and passed to t he VCO to control the oscillator f r equency. (See Fig. 4 of Next Page)

PLL DATA

REF OSC

I/N

I/M

PLL IC IC1

5KHz/6.25KHz

PHASE

COMPARATOR

5KHz/6.25KHz

CHARGE

PUMP

LPF

D2.4Q4TX VCO

D1.3Q3RX VCO

BUFF AMP

Q5.7

T/R SW

Q2 RF AMP

12.8MHz

Fig. 4. PLL circuit

2) VCO

The operati ng frequency is generated by Q4 in transmit mode and Q3 in receive mode. The oscillator frequency is controlled by apply ing the VCO control volt age, obtained from the phase comparator, to t he varactor diodes (D2 and D4 in transmit mode and D1 and D3 in receive mode) . The T/R pi n is set hig h i n receive mode causing Q5 and Q7 to turn Q4 off, and turn Q3 on. T he T/R pin is set low in transmit mode. The outputs fr om Q3 and Q4 are amplified by Q6 and sent to the buffer amplifiers.

3) UNLOCK DETECT OR

If a pulse signal appears at t he LD pin of I C1, an unlock conditio n occurs, and the DC voltage obtai ned from D7, R6, and C1 causes t he voltage applied to t he UL pin of t he microprocessor to go low. When the microprocessor detects this condition, the transmitter is disabled, ignoring the push-to-talk switch input signal. (See Fig. 5)

IC1

PLL IC

IC403

MPU

4. Transmitter

1) Transmit audio

The modulatio n signal from the microphone is amplified by IC500 (1/ 2), passes through a pr eemphasis circuit, and amplified by the ot her IC500 (1/2) to perform IDC operation. The sig nal then passes thro ugh a low-pass f ilter (splatt er filter) (Q501 and Q502) and cuts 3kHz and higher frequencies.

Fig. 5. Unlock detector circ uit

RPU416A Circuit Description

ANT

The resulting sig nal goes to the VCO through the VCO mod ulation terminal for direct FM modulation. ( See Fig. 6)

2) QT/ DQT encoder

A necessary signal for QT/DQT encoding is generated by IC403 and FM-modulated to the PLL refer ence signal. Since the refer ence OSC does not mod ulate the loop characterist ic frequency or higher, modulatio n is perfor med at t he VCO side by adjusting the balance. ( See Fig. 6)

IC500(1/2)

MIC AMP PREEMPHASIS

IC500(1/2)

IDC

Q501.502

LPF

(SPLATTER FILTER)

VR501

MAX DEV D5.Q4

MIC

Q503 SW

MUTE

IC403

QT/DQT

VR500 BALANCE

VCO

X1.IC1

REFERENCE

OSC

Fig. 6. Transmit audio QT/DQT

3) RF amplifier

The transmit signal obtai ned from the VCO buffer amplifier Q100, is amplified by Q101 and Q102. This amplified signal is passed to the power amplifier, Q105 and Q107, w hich consists of a 2-stage FET amplifier a nd is capable of produci ng up to 4W of RF power (See Fig. 7-b)

AMP

Q101.102

DET

Q103.Q104

B SW

DRIVE AMP

Q105

APC

IC100

Q109

FINAL AMP

Q107

ANT SW

D101 LPF

APC

TH102

Q110

4) ANT switch and LPF

The RF amplifier output signal is passed t hro ugh a low-pass filter networ k and a transmit/receive

Q108 SW

Fig. 7 APC system

Q106 SW

ANT SW D102.103

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HYT RPU416A User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual