Circuit Description
UHF1 (400
–
470 MHz)
28
Registers
MSB/LSB
Dividend
Divider
PD/Charge Pump
& Pwr-Dn/Mux Out
Control
Reference
Frequency Dividers
Serial
Interface
Modulation
Unit
Fractional
Unit
ΔΣ
18-Bit
Main
Divider
Main
Divider
Main Phase/
Freq.Detector
and
Charge Pump
Reference
Frequency
Oscillator
Reference
Frequency
Oscillator
M
ux
Mux_out
Ref
Data
Clock
CS
Mod_in
Fvco_main
Fvco_main
CPout_main
LD/PS_main
Lock Detection or
Power Steering
Fref_main
Fref_main
The 19.2 MHz frequency generated by the crystal oscillator (X100) goes into the PLL IC (U100) for
frequency division, generating the reference frequency. Meanwhile, the frequency generated by VCO
goes into PLL IC (U100) for frequency division. The resulting frequency will be compared with reference
frequency in terms of phase difference in the phase detector. After comparison, the resulting frequency
is converted to CV voltage via the loop filter, to control and lock the frequency.
Voltage-Controlled Oscillator (VCO)
PLL IC
U100
Q103
L P F
Q110
Q100
Q106
Q102
Q107
MOD
Q111
Q109
TX_L_VCO
RX_L_VCO
TX_H_VCO
RX_H_VCO
TX PA
RX Lo
The VCO is composed of transistors (Q100, Q103, Q106 and Q110), varactors and four Colpitts
oscillators. There are four VCOs in all: two VCOs (Q100 and Q103) used to transmit excitation signals
Содержание MD78X
Страница 1: ...DIGITAL MOBILE RADIO SERVICE MANUAL...
Страница 5: ...UHF1 400 470 MHz...
Страница 14: ...UHF1 400 470 MHz Exploded View and Packing Guide 7 3 2 Packing Guide...
Страница 56: ...UHF1 400 470 MHz Interface Definition 49 Pin No Name Description 39 GND Grounding 40 PWB_IN Power On Off signal...
Страница 62: ...55 9 PCB View MD78X MD78XG PCB View Front Panel Top Layer...
Страница 63: ...56 MD78X MD78XG PCB View Front Panel Bottom Layer...
Страница 64: ...MD78X MD78XG PCB View Main Board Top Layer 57...
Страница 65: ...MD78X MD78XG PCB View Main Board Bottom Layer 58...
Страница 111: ...UHF2 450 520 MHz...
Страница 120: ...UHF2 450 520 MHz Exploded View and Packing Guide 7 3 2 Packing Guide...
Страница 167: ...54 9 PCB View MD78X MD78XG PCB View Front Panel Top Layer...
Страница 168: ...55 MD78X MD78XG PCB View Front Panel Bottom Layer...
Страница 169: ...MD78X MD78XG PCB View Main Board Top Layer 56...
Страница 170: ...MD78X MD78XG PCB View Main Board Bottom Layer 57...
Страница 216: ...UHF3 350 400 MHz...
Страница 225: ...UHF3 350 400 MHz Exploded View and Packing Guide 7 3 2 Packing Guide...
Страница 272: ...54 9 PCB View MD78X MD78XG PCB View Front Panel Top Layer...
Страница 273: ...55 MD78X MD78XG PCB View Front Panel Bottom Layer...
Страница 274: ...MD78X MD78XG PCB View Main Board Top Layer 56...
Страница 275: ...MD78X MD78XG PCB View Main Board Bottom Layer 57...
Страница 321: ...UHF5 806 941 MHz...
Страница 330: ...UHF5 806MHz 941MHz Exploded View and Packing Guide 7 3 2 Packing Guide...
Страница 376: ...53 9 PCB View MD78X MD78XG PCB View Front Panel Top Layer...
Страница 377: ...54 MD78X MD78XG PCB View Front Panel Bottom Layer...
Страница 378: ...55 MD78X MD78XG PCB View Main Board Top Layer...
Страница 379: ...56 MD78X MD78XG PCB View Main Board Bottom Layer...
Страница 414: ...VHF 136 174 MHz...
Страница 423: ...VHF 136MHz 174MHz Exploded View and Packing Guide 7 3 2 Packing Guide...
Страница 468: ...PCB 52 9 PCB View MD78X MD78XG PCB View Front Panel Top Layer...
Страница 469: ...PCB 53 MD78X MD78XG PCB View Front Panel Bottom Layer...
Страница 470: ...MD78X MD78XG PCB View Main Board Top Layer 54...
Страница 471: ...PCB 55 MD78X MD78XG PCB View Main Board Bottom Layer...