GB562779A - Improvements in radio receivers - Google Patents

Abstract

562,779. Wireless receiving systems. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. Jan. 12, 1943. No. 535. Convention date, Sept. 12, 1941. [Class 40 (v)] In a radio receiver the received energy is selectively separated into three bands, one containing the carrier and each of the other bands containing one sideband, and separate means are provided for combining and rectifying each of the sidebands with a portion of the carrier, together with means for combining the outputs of the rectifiers so that the effect of frequency selective fading is reduced. The Figure shows an arrangement of a superheterodyne receiver in which the upper and lower sidebands of the intermediate frequency are passed by channels 4, 6 respectively and the carrier by the channel 5 and coupled through units 8 ... 11 to rectifiers 12, 13. Automatic volume control may be applied to the high-frequency amplifier through a unit 14 and a portion of the energy in the sideband channels may be applied through transformers 15, 16 to rectifiers 17, 18 arranged in opposition so that a control voltage is desired. A phase reversing valve 21 also produces an equal voltage in phase opposition and these voltages so control the gain in the channels 4, 6 as to increase the gain in the channel with larger signal and to decrease the gain in the other channel. The carrier 'channel 5 may include a limiter 7. A pair of such receivers may be used with separate aerials to take advantage of spaced or polarized diversity reception.