Telemetering system for the X-17 missile

This paper describes the circuits, components and packaging of a high performance airborne six-channel FM/FM telemetering system developed by the Lockheed Missile Systems Division for use in the Air Force X-17 Missile Program. The package, weighing 31–1/2 pounds and measuring 8 inches in diameter by 14 inches long obtains highly accurate information under the severe environmental conditions encountered by a hypersonic ballistic missile. By utilizing time division multiplexing on four channels, 79 quantities are measured. A bridge-modulated subcarrier oscillator permits the use of variable reluctance transducers on commutated channels. Where possible, plug-in components were reduced in size by transistorization, printed wiring boards, and encapsulation techniques. The antenna coupling device is a radial folded cavity which carries the full structural load, and permits excitation of longitudinal r-f currents on the surface of the vehicle. The philosophy and techniques associated with the development and application of this system resulted in many useful features providing exceptionally high information capacity, accuracy, reliability, and versatility.