Final rept. 15 Jun 1967-15 Mar 1968
RADIO CORP OF AMERICA NEW YORK ADVANCED COMMUNICATIONS LAB
Pagination or Media Count:
A study was made of the feasibility of using a Single-Frequency Repeater for extending the range voice of the ANPRC-25 Radio Set. A feasibility model was designed using the principle of chopped, delayed voice constructed and tested in a limited manner. Test results are presented, as are general description and operating instructions. The results of the work done so far indicate that Single-Frequency Repeating can be used to repeat a voice- modulated, FM, RF signal and still retain some measure of intelligibility at the Receiving Terminal. The distance to which the effective range of a pair of AN PRC-25 Radio Sets can be extended, using the model Repeater is not yet known, mostly because of insufficient performance measurements. Considerable extension is unquestionably possible if the modified ANPRC-25 Retransmitter is replaced with a suitable Retransmitter. Some improvements to intelligibility can also be made, as evidenced by the limited experiments already carried out. One, for example, would be to implement synchronous audio blanking at the Remote Receiver during idle non-transmit times, thus eliminating the inevitable Receiver noise. Another would be to improve the quality of the audio input to the Retransmitter it presently suffers from severe distortion. For example, an AGC amplifier used in place of the existing limiting arrangement would certainly offer significant improvement. Still other improvements could occur from optimizing the chopping rate, Guard Band, and the AF responses at both the Repeater and Remote Receivers.
- Radio Communications