DRS WJ-8611 Installation, Operation And Maintenance Manual Download

Page: 139 / 301

WJ-8611 DIGITAL VHF/UHF RECEIVER

CIRCUIT DESCRIPTIONS

5-19

DATA signal carries the lower sideband audio. The lower sideband signal
is sent to the LINE B and LEFT PHONES outputs. The upper sideband is
sent to the LINE A and RIGHT PHONES output.

The timing for the circuitry in the Digital Control PC Assembly (A2) is
derived from a 100 MHz reference signal entering the assembly at
connector A2J4. This reference is supplied to a clock distribution circuit
in the Control Processor section where a series of frequency dividers
develop and distribute the individual clock signals. A divide-by-five
divider, followed by a frequency doubler circuit, produces a 40 MHz clock
for use by the Programmable Serial I/O Digital Filters in the Control
Processor section, and by the Digital-to-Analog converter (D/A) in the
Reconstruction and Output section. This 40 MHz clock is also used by
two programmable Flexible Logic circuits to clock the control logic and
produce additional timing and synchronization signals for the operations
performed by the Digital Control PC Assembly (A2). The 40 MHz clock
signals are available at test points TP4, TP5, and TP6. The remaining
outputs from the clock distribution circuit provide the Control Processor
section with its microprocessor and IEEE-488 clock signals. The 100
MHz reference signal is divided by a factor of six to produce the 16.6 MHz
(16.67 MHz) control microprocessor clock. The clock is further divided
(by a factor of 4) to obtain a 4.2 MHz (4.167 MHz) clock for use by the
IEEE-488 remote interface.

5.4 TYPE 797229-1 FRONT PANEL ASSEMBLY (A1) CIRCUIT DESCRIPTION

The Front Panel Assembly (A1) consists of the Part 482554-2 Front Panel
Control PC Assembly (A1A1), the Part 482929-1 Display PC Assembly
(A1A2), and the Part 383947-1 Interconnect PC Assembly (A1A3) as
shown in

Foldout FO-14

. This assembly provides the man/machine

interface to the WJ-8611 Digital VHF/UHF Receiver. Refer to the Front
Panel Assembly (A1) Functional Block Diagram in

Foldout FO-7

as a

reference for the following assembly description.

Within the sub-assemblies listed above, the Front Panel Assembly (A1) can

be broken down into four functional sections: the Control and Interface
section; the Dot Matrix Display section; the Switch/Indicator and Keypad
section; and the Frequency, Tune Meter and Miscellaneous Indicator
Display section.

The Control and Interface section maintains all front panel operations and
consists of a 16-bit microcontroller, memory circuits, motion encoders, and
an RS-232 Interface. The 16-bit microcontroller processes all operator
inputs, updates the displays and indicators, and performs the interface to
the Digital Control Assembly (A2) for receiver control. Likewise, new
display data from the Digital Control Assembly (A2) is processed by the
front panel microcontroller. This occurs during power up to initialize the
display to its power down status or to provide updates of changing
parameters associated with memory or remote operations. Full-duplex,
serial communications with the Digital Control Assembly (A2) is
performed using an RS-232 Driver/Receiver.

DRS WJ-8611, Installation, Operation And Maintenance Manual

Search results

Summary of Contents for WJ-8611

Reviews:

Related manuals for WJ-8611

Brands by name

Popular brands