DRS WJ-8611, Инструкция по установке, эксплуатации и обслуживанию

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WJ-8611 DIGITAL VHF/UHF RECEIVER
GENERAL DESCRIPTION 1-1
SECTION 1 GENERAL DESCRIPTION
1.1 ELECTRICAL CHARACTERISTICS
The WJ-8611 Digital VHF/UHF Receiver is a fully synthesized general
purpose surveillance receiver that combines a high quality analog RF tuner
with the power of a Digital Signal Processing-based (DSP-based) IF and
Demodulation section. It tunes over a 2 to 1000 MHz frequency range,
with a 10 Hz tuning resolution (specifications apply in the 20 to 1000 MHz
range). The standard receiver offers a selection of seventeen IF
bandwidths ranging from 200 Hz to 200 kHz. The detection mode
selections are AM, FM, CW, SSB, and ISB. A five-band tracking
preselector, at the receiver front end, improves performance by limiting the
interfering signals at the input. The preselector tracks with the tuned
frequency and limits the input spectrum to approximately 20% of the tuned
frequency. The detailed specifications for the WJ-8611 Digital VHF/UHF
Receiver are provided in
Table 1-1 .
Accurate frequency tuning is provided using analog coarse tuning, coupled
with DSP controlled fine tuning. The coarse tuning is provided by three
synthesized local oscillators that provide an analog IF output with a 1 kHz
tuning resolution. A highly stable 10 MHz internal reference, with a
±
0.5
x 10
-6
accuracy, is used as the common time base for the synthesizer
circuits. Fine tuning to a 10 Hz resolution is performed using a DSP
algorithm after the signal has been digitized.
Many of the receiver functions such as fine tuning, IF filtering, gain
control and demodulation are performed digitally, using DSP techniques.
This results in stable, repeatable performance over a wide range of
operating conditions. Digital filters produce IF filter performance with
superior amplitude and group delay characteristics.
The receiver provides a 21.4 MHz IF output that is derived from the analog
circuitry of the RF assembly, and audio and video outputs that are
reconstructed into analog signals after the signal has been processed by the
DSP circuits. A digital IF output is provided for use with external digital
signal processing equipment. It consists of the complex In-phase (I) and
Quadrature-phase (Q) components of the received signal. A pre-detected
250 kHz IF output is also provided.
In addition to manual operation, the WJ-8611 Digital VHF/UHF Receiver
provides flexible scanning capabilities, using a user programmable 200
channel memory, a search memory, and group of dedicated memory
control keys that permit memory programming and activation of automatic
operating modes such as F1-F2 and Channel scans.
The standard receiver supports remote control from either a serial or a
parallel interface. It can be configured for single-drop, full-duplex
RS-232C or IEEE-488 operation. Internal switches determine which
interface is active and its operating characteristics. The configuration may
be modified in the field to accommodate a wide range of controlling
devices.
Courtesy of http://BlackRadios.terryo.org