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Service Manual
6. UHF1 (400-470 MHz) Information
34
6.3.2 Working Principle of VCO
VCO employs Colpitts oscillator circuit (the RX oscillator circuit comprises D6014, D6015,
D6016, D6017and L6061; the TX oscillator circuit is composed of D7001, D7002, D7004,
D7005, and L7007). It obtains different output frequencies by changing the varactor diode’s
control voltage (i.e. CV voltage). There are two types of VCO: TX VCO and RX VCO. Both
types control EMD22 to switch operating status via OMAP. RX VCO consists of the oscillator
loop and Q6012, to provide LO signal. TX VCO is composed of the oscillator loop and Q7003,
to provide carrier for TX signal.
6.3.3 Two-Point Modulation
In TX mode, the two-point modulation technology is employed, to obtain higher modulation
accuracy and lower 4FSK bit error rate. MOD-VCO and MOD-XO send the modulation signal
to the modulation end of VCO and the reference oscillator of PLL respectively to modulate TX
VCO and the reference crystal oscillator.
Summary of Contents for RDR9000
Page 1: ...RDR9000U V Service Manual ...
Page 45: ...Service Manual 6 UHF1 400 470 MHz Information 35 6 4 PCB View PCB View Main Board Top Layer ...
Page 46: ...Service Manual 6 UHF1 400 470 MHz Information 36 PCB View Main Board Bottom Layer ...
Page 48: ...Service Manual 6 UHF1 400 470 MHz Information 38 PCB View Rear Board Top Layer ...
Page 146: ...Service Manual 7 UHF3 350 400 MHz Information 136 7 4 PCB View PCB View Main Board Top Layer ...
Page 147: ...Service Manual 7 UHF3 350 400 MHz Information 137 PCB View Main Board Bottom Layer ...
Page 149: ...Service Manual 7 UHF3 350 400 MHz Information 139 PCB View Rear Board Top Layer ...
Page 248: ...Service Manual 8 VHF 136 174 MHz Information 238 8 4 PCB View PCB View Main Board Top Layer ...
Page 249: ...Service Manual 8 VHF 136 174 MHz Information 239 PCB View Main Board Bottom Layer ...
Page 251: ...Service Manual 8 VHF 136 174 MHz Information 241 PCB View Rear Board Top Layer ...
Page 346: ...Service Manual 11 Packing Guide 336 11 Packing Guide Figure 11 1Packing Guide ...
Page 352: ...342 ...