Rca1948FrequencyModu.. - The New Jersey Antique Radio Club

DUPLEX SOUND AND FACSIMILE 4055. Laboratory Tests of Duplex TransmissionThe first laboratory tests were of a preliminary nature and useda special receiver (with audio circuits similar to those in Figure 7)and a signal generator set at 43.5 megacycles. The facsimile signalwas as previously described, and the aural channel was fed by a beatoscillator or from a phonograph pickup. In these tests the receiverbandwidth was slightly higher than 200 kilocycles and good resultswere expected with the full aural deviation of 75 kilocycles and afacsimile deviation of 15 kilocycles. A tabulation of the results obtainedfollows:Audio