Ajetrays AJ447 Manuel utilisateur
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AJETRAYS
MODEL AJ447
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SPECIFICATION
GENERAL
FREQUENCY RANGE………………………………………….. 400-470MHz
CHANNEL NUMBER…………………………………………… 16
CHANNEL STEP………………………………………………… 25kHz
FREQUENCY GENERAL……………………………………….. SYNTHESIZER (PLL)
MODULATION TYPE…………………………………………… FM (F3E)
DIMENSION……………………………………………………… 107(H)×53(W)×29.5(D)mm
WEIGHT (WITH BATTERY&BATTERY)……………………….. Approx. 215g
RECEIVER
SENSITIVITY…………………………………………………….. < 0.30μVat 12dB SINAD
SELECTIVITY……………………………………………………. 65dB
SPURIOUS RESPONSE………………………………………….. 65dB
DISTORTION…………………………………………………….. LESS THAN 5%
AUDIO OUPUT POWER…………………………………………500mW at 8Ω
TRANSMITTER
POWER OUTPUT………………………………………………… 4W
FREQUENCY STABILITY………………………………………. ±2.5ppm (-20ºC ~ +60ºC)
HARMONIC AND SPURIOS EMMISION……………………… 60dB
FREQUENCY DEVIATION……………………………………… NOT MORE THAN ±5.0kHz
AUDIO DISTORTION……………………………………………. LESS THAN 5%
MAIN PC BOARD(TOP VIEW)
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MAIN PC BOARD CIRCUIT(TOP VIEW)
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MAIN PC BOARD(BOTTOM VIEW)
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MAIN PC BOARD CIRCUIT(BOTTOM VIEW)
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ADJUSTMENT INSTRUMENT LIST
INSTRUMENT SPECIFICATION
Standard Signal
Generator
Frequency Range: 1 ~ 500MHz
Output Level: 0.1uV ~ 50mV
Digital Voltmeter Measuring Range: 1mV ~ 15V
Distortion Meter Measuring Range: 0.1 ~ 20%
Frequency Counter Frequency Range: 1 ~ 500MHz
Accuracy: ±1ppm or Better
Sensitivity: 100mV or Better
Oscilloscope Frequency Range: DC ~ 20MHz
Measuring Range: 0.01 ~ 15V
RF Power Meter Measuring Range: 0.1 ~ 10W
Frequency Range: 1 ~ 500MHz
Impedance: 50ohm
Stabilized Power Supply Output Voltage: 0 ~ 15V DC
Output Current: 3A or more
External Load Connection Type: 3.5Φmono
Impedance: 8ohm/2W
FM Modulation Analyzer Frequency Range: 20Hz ~ 5kHz
Measuring Range: 0 ~ ±10kHz
Audio Signal Generator Frequency Range: 20Hz ~ 3kHz
Output Level: 1mV ~ 1V
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ADJUSTMENT PROCEDURES
TRANSMITTER SECTION
Item Condition Measurement Adjustment Specifications/
Test Equipment Terminal Parts Method Remarks
1. Transmit 1) CH: TX Lo RF Power Meter ANT SOFTWARE Adjust it to 4W
Power PTT: ON Ammeter PROGRAM Check
2. Transmit 1) CH: TX Center Frequency ANT SOFTWARE Adjust to ±500Hz
Frequency PTT: ON Counter PROGRAM or less
3. Modulation 1) CH: TX Center Modulation ANT SOFTWARE Adjust to ±2.5kHz
Analyzer PROGRAM
Oscilloscope MIC
Audio Signal
Generator
4.CDCSS
Balance
Adjust
CH: TX Center
PTT: ON
Modulation
Analyzer
Oscilloscope
ANT
SOFTWARE
PROGARM
Make the
Demodulation wave
into square waves
RECEIVER SECTION
Item Condition Measurement Adjustment Specifications/
Test Equipment Terminal Parts Method Remarks
1) CH: RX Center Oscilloscope ANT SOFTWARE Adjust to just turn
1. Squelch MONI: ON Distortion meter SPK PROGRAM on the squelch
1) CH: RX Lo Oscilloscope ANT SOFTWARE Adjust to the min.
2. Sensitivity CH: RX Center Distortion meter SPK PROGRAM Distortion and best SINAD 12dB
CH: RX Hi Signal to noise ratio
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CIRCUIT DESCRIPTION
1. IC DESCRIPTION
The RDA1846 is a highly integrated single-chip transceiver for Walkie Talkie applications. The
RDA1846 has a powerful digital signal processor, which makes it have optimum voice quality ,flexible
function option ,and robust performance under varying reception conditions.
2. RECEIVER SYSTEM
2-1 Front End (RF AMP)
The signal coming from the antenna passes through the Transmit / Receive switching diode circuit,
passes through a BPF ( L7 and L10), and is amplified by the RF amplifier (Q2). The resulting signal p
goes to RF signal processing IC6 (RDA1846)..
2-2 RF input
Received from the antenna to the RF signal amplified by the LNA(Q2) into IC6 (RF signal processing
IC).RF signals in the chip (IC6) within the amplification, mixing, analog / digital conversion, digital
signal processing (DSP) and analog / digital converter, the output audio signal through the chip PIN
9,enters the microprocessor MCU(IC3).
2-3Receive Signaling(CTCSS/CDCSS)
The output signal from IC6(RDA1846) enters the microprocessor(IC3). IC3 determines whether the
CTCSS or CDCSS matches the preset value, and controls the SP MUTE and the speaker output sounds
according to the squelch results.
2-4 AF Amplifier
The AF signal from the IC is amplified and decoded by MCU (IC3), and the signal passes through AF
VOL circuit and enters the audio power amplifier IC4 (TDA2822) to drive the speaker.
2-5 Squelch
RF signal strength testing done by the IC6. Detecting level values are compared with the default values,
will determine the output to the microprocessor(IC3) to control the audio power amplifier(IC4) is
working. To output sounds from the speaker, microprocessor(IC3) sends a high signal to the MUTE and
turns IC4.
3. TRANSMITTER
3-1 Transmit Audio
The signal from the microphone passes through the IC3. The signal passes through the SOFTWARE
PROGRAM for the maximum deviation adjustment, and goes to the IC6 modulation input.
3-2 CTCSS/CDCSS Encoder
A necessary signal for CTCSS/CDCSS encoding is generated by the IC6, and transmits through RF
circuit.
3-3 RF Amplifier
The RF signal from the IC6 RF Output is amplified by Q12,Q11and Q14 to the sufficient level to drive
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the power module.
3-4 Final Module
The UHF power transistor RQA0009 is used to amplify the transmission power.
3-5 ANT Switch and LPF
The signal from the power transistor passes through the L2, L3 and L4 LPF and is output from the ANT
terminal. IC3 and PTT are used to switch between transmission and reception.
3-6 Control System
The CPU IC3 operates at 32.768KHz clocks.
3-7 Power Supply
The main of the system control is DC7.4V.
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