Battery operated radio receiver

Abstract

Abstract 1,111,006. Transistor circuits; radio sigrialling. PYE Ltd. 4 March, 1966 [9 March, 1965], No. 9850/65. Headings H3T and H4L. In order to obtain reduced power consumption from the direct current supply to a radio receiver in the absence of a signal, the direct current path to the receiver is made alternately conductive and non-conductive by switch means, the path being held conductive on the advent of a signal. The receiver is connected between points b, c, and the supply of current is controlled by switch VT6, which is in turn controlled by a free-running multivibrator VT3, VT4 such that the non-conducting periods of switch VT6 are about five times longer than the conducting periods, and the frequency of operation is sub-audio (e.g. 2 c/s.). Should a signal be received during a conductive period of switch VT6, a positive voltage is derived from the receiver and applied to point 7, switching transistor VT1 on to charge capacitor C1 rapidly through diode D1. Transistor VT2 accordingly switches on, disabling the multivibrator and holding it in the state in which switch VT6 is held on. At the end of the received signal, transistor VT1 switches off, and capacitor C1 discharges slowly through transistor VT2. Such slow discharge delays the enabling of the multivibrator after the end of the signal to guard against switch VT6 being switched off during any momentary pauses in the signal. The voltage applied to point 7 may be derived from the collector of a squelch gate transistor, may be an alternating voltage rectified within circuit 5, or a D.C. signal obtained from modulation of an incoming carrier by information or a pilot tone.

Inventors

• 👤 Peter A Webster
• 👤 Dennis A Clare
• 👤 John Raymond Brinkley

Bibliographic Details