Command Transmitter System

System Planning Corproation's Command Transmitter Systems (CTS) provide remote control and flight termination functions through a fully-redundant self-contained solid-state system.

The exciter incorporates state-of-the-art Direct-Digital-Synthesis technology to simultaneously generate an RF carrier and up to 6 of 20 available standard IRIG-B tones. It has 20 watts of output power and an internal ferrite isolator. The exciter may also be used as a standalone unit.

High-Power Amplifier
The high-power amplifier (HPA) is solid-state, dependable, and cool running, allowing continuous 1-kW output power at temperatures from 0o to 50oC, and from sea level to 30,000 feet AMSL. The Command Transmitter System is MIL-STD-461C qualified and designed to military standards for high MTBF and continuous 24-hour-per-day operation.

State-of-the-art CMOS micro-controllers provide full fault detection and reporting. High-power ferrite isolators allow full-power operation with antenna VSWRs up to 2:1. The HPA is designed for graceful degradation, which allows high-output power operation even with several amplifier modules inoperative. As an optional feature, each HPA sub-system is provided with an RF switch matrix that allows real-time replacement of HPA units.

External modulation inputs may be used to modulate the transmitters with externally-generated tones from 10 Hz to 100 kHz.

The system can be switched automatically or manually between transmitters. Automatic switching to the redudant system is completed in less than 5ms upon detection of an internal fault or at preset RF power thresholds. The system is mounted in two standard 60"-high racks for easy installation in mobile platforms. The roller-bearing, tiltable rack slides allow easy access within the chassis for low MTTR. CTS generally ships with front panel button operation for broadcast frequency and tones. Add-on options are available from SPC for remote control features. For more information on an integrated control system, see SPC's Flight Termination System

Download a CTS brochure.

CTS Specifications
Performance Feature FTS Specification
Frequency Range: 400-550 MHz in 100-kHz steps
RF Output Power: Exciter: 20 Watts; HPA: 1 kW
RF Power Control: 1-dB steps, 60-dB total range
Permissible Antenna VSWR: > 2:1 continuously, 50 ohms nom.
Harmonics: < -50 dBc at 1 kW
Spurious: < -80 dBc at 1 kW
Modulation: FM
Deviation: ± 300 kHz
Modulation Range: Internal: 7.5-73.95 kHz (IRIG-B tone frequencies)
Prime Power: 180-228 VAC 3-phase Wye connection, 47-63 Hz; 5 kVA maximum per rack, two connectors required (supplied); entrance at bottom center of each rack
Local Control, RF Power Monitor, and Exciter are supplied 120 VAC nom. single-phase by the HPA power supply
Cooling: Forced air; all exhausts through rear panels
Controls and Indicators
Local Control:
  • Automatic or manual
  • Either transmitter as primary or secondary Local/Remote
  • Alarm reset and audio alarm disable
  • System fault
  • Overtemperature fault
  • Power on/off
RF Power Monitor:
  • Forward and reflected RF output power level
  • Forward and reflected RF output power fault
  • Overtemperature
  • Local/Remote
  • Carrier enable, carrier on
  • RF output power attenuator
  • RF carrier frequency
  • Selected audio tone (up to 6 of 20)
  • Deviation
  • Deviation monitor
  • Compressor on/off and limit set
  • Overtemperature fault
  • Power on/off
HPA: Overtemperature
HPA Power Supply:
  • Line power (indicators)
  • System power (circuit breaker/switch)
  • HPA 28-volt power (circuit breakers/switches,Indicators)
  • Overtemperature
Dimensions: 2 standard 19" racks, 32" deep and 60" high
Antenna Connectors: Female type LC, mounted on left-rear upper rack surfaces
Weight: Approx. 800 lb/rack


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