Engineering topics
Publications and source records attributed to Timor, U..
Simple addition to hardware and new mode of operation of transmitter and receiver in coherent, PCM/PSK/PM configuration greatly improves channel efficiency. Procedure reduces amount of power lost to intermodulation products.
A two-channel telemetry system is described in which one channel is used for high-rate data and the other channel for low-rate data communication. In the transmitter a signal, which subsequently phase modulates a carrier, is produced which is a function of at least the high-rate data, the low-rate data and the frequency of the subcarrier of the low-rate channel. In the receiver which includes a phase-locked loop, the high-rate data is detected off the receiver inphase channel output and the low-rate off the quadrature channel output.
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In comparing different techniques for multiplexing N binary data signals into a single channel, time-division multiplexing (TDM) is known to have a theoretic efficiency of 100 percent (neglecting sync power) and thus seems to outperform frequency-division multiplexing systems (FDM). By considering more general FDM systems, we will show that both TDM and FDM are equivalent and have an efficiency of 100 percent. The difference between the systems is in the multiplexing and demultiplexing subsystems, but not in the performance or in the generated waveforms.
N-channel PSK/PM digital telemetry system modulation scheme for space exploration
Optimum and suboptimum decision rules for two- channel deep space telemetry system with modulation consisting of PM with two orthogonal phase functions
PSK signals time division multiplexing and frequency multiplexed subcarrier systems equivalence and efficiency for digital communications
Multichannel PCM/PSK/PM interplex telemetry system for reducing cross modulation loss and excess carrier reference power
Description of a multichannel PCM-PSK-PM modulation scheme called interplex which reduces cross-modulation loss and excess carrier reference power of conventional systems when the number of channels is small. In systems with equal channels, interplex is more efficient when the number of channels is not greater than four. The number of channels which can be combined efficiently with interplex increases if there are many low-power channels and only one high-power link. The scheme can be implemented in existing systems without significant hardware changes and appears to be suitable for use in a multichannel space-station telecommunications system.
Weak noise and threshold effects on estimation error for nonlinear PM systems
Suppressed RF carrier tracking for two channel interplex phase modulated telemetry