![RCA RDR9000 Скачать руководство пользователя страница 141](http://html.mh-extra.com/html/rca/rdr9000/rdr9000_service-manual_335287141.webp)
Service Manual
7. UHF3 (350-400 MHz) Information
131
7.1.2 Low-Pass Filter Circuit
The low-pass filter is a high
–order Chebyshev filter composed of lumped-parameter inductors
and capacitors. Via this filter, the spurious signal within the stop band can be attenuated as
much as possible while the in-band ripple is within the required range.
7.1.3 Auto Power Control Circuit
In the auto power control and temperature detection circuit, the drain current from the driver
amplifier and final-stage amplifier is converted to voltage via the sampling resistor and
subtraction circuit (composed of the first operational amplifier). This voltage is compared with
the APC control voltage (output by DAC) at the second operational amplifier. Then the error
voltage, which is output by the second operational amplifier, controls TX power by controlling
the bias voltage at the gates of the amplifiers (including the driver amplifier and the final-stage
amplifier). The temperature sensor detects the surface temperature of the final-stage
amplifier, and then converts it to DC voltage. Then the DC voltage is compared with the
voltage corresponding to the protection temperature (generally 80% of the extreme
temperature) of the amplifier. If the surface temperature is too high, the bias voltage of the
amplifier will be reduced until the surface temperature falls below the protection temperature.
Содержание RDR9000
Страница 1: ...RDR9000U V Service Manual ...
Страница 45: ...Service Manual 6 UHF1 400 470 MHz Information 35 6 4 PCB View PCB View Main Board Top Layer ...
Страница 46: ...Service Manual 6 UHF1 400 470 MHz Information 36 PCB View Main Board Bottom Layer ...
Страница 48: ...Service Manual 6 UHF1 400 470 MHz Information 38 PCB View Rear Board Top Layer ...
Страница 49: ...Service Manual 6 UHF1 400 470 MHz Information 39 PCB View Rear Board Bottom Layer Figure 6 5 PCB View ...
Страница 146: ...Service Manual 7 UHF3 350 400 MHz Information 136 7 4 PCB View PCB View Main Board Top Layer ...
Страница 147: ...Service Manual 7 UHF3 350 400 MHz Information 137 PCB View Main Board Bottom Layer ...
Страница 148: ...Service Manual 7 UHF3 350 400 MHz Information 138 PCB View Control Head Top Layer PCB View Control Head Bottom Layer ...
Страница 149: ...Service Manual 7 UHF3 350 400 MHz Information 139 PCB View Rear Board Top Layer ...
Страница 150: ...Service Manual 7 UHF3 350 400 MHz Information 140 PCB View Rear Board Bottom Layer Figure 7 5 PCB View ...
Страница 248: ...Service Manual 8 VHF 136 174 MHz Information 238 8 4 PCB View PCB View Main Board Top Layer ...
Страница 249: ...Service Manual 8 VHF 136 174 MHz Information 239 PCB View Main Board Bottom Layer ...
Страница 250: ...Service Manual 8 VHF 136 174 MHz Information 240 PCB View Control Head Top Layer PCB View Control Head Bottom Layer ...
Страница 251: ...Service Manual 8 VHF 136 174 MHz Information 241 PCB View Rear Board Top Layer ...
Страница 252: ...Service Manual 8 VHF 136 174 MHz Information 242 PCB View Rear Board Bottom Layer Figure 8 5 PCB View ...
Страница 346: ...Service Manual 11 Packing Guide 336 11 Packing Guide Figure 11 1Packing Guide ...
Страница 352: ...342 ...