Modulators, Uplink RF, IF & Sub-Carrier

Model 782 Tunable PSK Subcarrier Generator (2U Chassis)
Model 782 Tunable PSK Subcarrier Generator

The Model 782 Tunable PSK Subcarrier Generator BPSK modulates a data stream at subcarrier frequencies up to 10 MHz. Local front panel control is provided through a high contrast vacuum-florescent display and keypad. English language menu selections allow rapid unit configuration and operation. Test automation is supported through an RS232 control port that allows remote setup by computer.

The Model 782 performs both coherent and non-coherent modulation. In coherent modulation applications, the Model 782 provides a TTL or RS-422 clock that is a submultiple of the subcarrier frequency. The data source, using this clock, provides a coherent modulation input to the Model 782. The modulated output signal is selectable between a sine wave and a square wave and can be adjusted in amplitude and offset up to ±10 volts. Data and clock is input to the unit as either TTL or RS-422. The data can be NRZ- (L,M,S) or BIØ-(L,M,S). The input data is converted to NRZ-L. This NRZ-L can be differentially encoded to NRZ-M or S. The subcarrier is then modulated by the differentially encoded data. The modulating data is also output to the rear panel allowing the Model 782 to function as both a Data encoder and decoder.

The unit can also serve as a general purpose frequency synthesizer for rates of 10 Hz to 10 MHz. The frequency output is selectable between sine and square waves.

  1. Non-Coherent and Coherent BPSK Modulation
  2. Tunable from I0 Hz to 10 MHz in 0.1 Hz Steps
  3. Data Codes - NRZ (L,M,S) and BIØ (L,M,S)
  4. NRZ Differential Encoding for Modulation
  5. Sine or Square Wave Modulation
  6. Accuracy & Stability 100 ppm (Optional I ppm)
  7. RS232 Remote Control
  8. Adjustable Output Signal Amplitude & Offset
  9. TTL & RS422 I/0

BPSK MODULATOR
DATA AND CLOCK INPUTS:
Selectable interface:
TTL signal levels, unbalanced; BNC connectors, DATA, CLK
RS422 signal levels, balanced voltage; Twinax connector, DATA, CLK
Input data rates:
DC to 1 Mbps
Data input code conversion:
Requires 0 degree clock input
Converts NRZ-L/M/S or BiPhase-L/M/S to NRZ-L
Selectable bypass (no conversion)

SUBCARRIER GENERATOR:
Frequency:
Tunable, 10 Hz to 10 MHz.
Resolution:
1 Hz
Combined Accuracy & Stability:

± 1 ppm

MODULATOR OUTPUT:
BPSK, 0/180 degree phase shift, sine or square wave output
Modulation Encoder:
Require 0 degree clock input
Converts NRZ-L to NRZ-L/M/S
Selectable bypass (no conversion)
Output level:
Adjustable Amplitude: 25 mV to 10 Vp -p
Adjustable Offset: 0 V to ±5V
Combined Signal + Offset restricted to ±10 V

COHERENT MODULATION:
Phase change at subcarrier zero crossing
MOD REF CLK synchronizes Data input

REFERENCE CLOCK OUTPUT:
MOD REF CLK:
TTL and RS422 Outputs
Frequency:
Subcarrier divided by 2N, where N=1 to 7, selectable

CODE CONVERTED MODULATION DATA AND CLOCK OUTPUTS:
Coded Data and Clock:
TTL and RS422
TTL Data and Clock:
RS422 Data and Clock

LOCAL FRONT PANEL CONTROL
VP DISPLAY AND KEYPAD:
(VF) display; 2-line by 40-character format
Twenty (20) position momentary-action keypad

IF OUTPUT AND LEVEL CONTROLS:
Ten (10) turn potentiometers, with “lock“

STATUS INDICATORS AND TEST POINTS:
Three (3) Front Panel Indicators:

Modulation Data In
Modulation Clock In (Red-Sig Loss; Green-Sig Present)
Modulation (Red-Modulation OFF; Green-Modulation ON)
Three (3) Front Panel Test Points:

IF Output-BPSK
Modulation Data In
Reference Clock

REMOTE CONTROL
RS232 SERIAL INTERFACE (STANDARD):
Asynchronous Half-duplex, 9600 baud

MISCELLANEOUS
AC Input:
115 / 230 Vac (Auto-select)
Single phase, 47-63 Hz
100 watts, max.
Size:
19 in. (W) x 3.5 in. (H) x 20 in. (D)
Weight:
15 lbs.
Mounting:
19 inch EIA equipment rack.
Non-tilting slides provided.
ENVIRONMENT:
Operating:
Temperature: +10 to +40, degrees C
R H: up to 95%, no condensation
Altitude: 0 to 10,000 ft

UPCONVERTER (Option)
70 MHz OUT:
BPSK RF Output
50 mVpp to 2 Vpp (50 Ohm Termination)
IF OUTPUT:
BPSK IF Output
50 mVpp to 10 Vpp (50 Ohm Termination)
REF CLK IN:
AC coupled
Switch selectable 1, 2, 5 or 10 MHz
REF CLK OUT:
AC coupled output
Switch selectable 1, 2, 5 or 10 MHz