GB633620A - Improvements in or relating to systems of transmitting signals by means of electro-magnetic waves - Google Patents

Abstract

633,620. Multiplex pulse signalling; radiolocation. PATELHOLD PATENTVERWERTUNGS- & ELEKTROHOLDING AKT.-GES. Nov. 9, 1945, No. 29896. Convention date, Nov. 13, 1944. [Classes 40 (v) and 40 (vii)] In a super-regenerative radio receiver for receiving one channel of an interlaced channel pulse multiplex system, the quench frequency being integrally related to the transmitter pulse train recurrence frequency, a switching device controls the back coupling periodically in such a manner that in the non-back-coupled phase the back coupling is completely cut off. As shown, the receiver oscillatory circuit K feeds the amplifier and demodulator R, the amplified H.F. signal being fed back to circuit K through a switching device U controlled by the quench generator P. The latter is synchronized to the channel pulse recurrence frequency by a pulse output from circuit R. The phase of generator P may be adjusted so that the incoming pulse coincides with the beginning of the build-up period of the oscillatory circuit. The output of the oscillatory circuit may be fed to the demodulator through a valve which is also controlled by the quench generator in such phase as to pass the signal at the end of the build-up period. The invention is applicable to pulses of frequency and phase-modulated radio frequency. Specification 585,613 is referred to. The Specification as open to inspection under Sect. 91 comprises' also an arrangement in which all the channel pulses are received by a single super-regenerative receiver and subsequently separated. The arrangement may also be used at a relay station, interference between the received and retransmitted pulses being avoided by a retardation element, a change of radio frequency or by a suitable disposition of aerials. When used in a radar system, the quench frequency may be obtained from the transmitter pulse recurrence frequency and its phase adjusted to give maximum sensitivity. This phase adjuster gives a rough indication of pulse transit time, but a further phase comparator is provided for accurate measurements. This subject-matter does not appear in the Specification as accepted.