Channel selecting apparatus in a receiver

Abstract

A superheterodyne receiver comprising a high frequency amplifier, a local oscillator implemented by a frequency synthesizer including a phase locked loop, a mixer, an intermediate frequency amplifier, an up down counter for providing data concerning frequency division rate of a programmable counter in the phase locked loop, characterized in that the up down counter is structured such that the counter is responsive to a command signal from an upward scanning switch to make an upward counting operation and is responsive to a command signal from a downward scanning switch to make a downward counting operation and is further responsive to command signals simultaneously obtained from these two upward and downward scanning switches to make a consecutive upward or downward counting operation, whereby a receiving channel is consecutively selected in the upward or downward direction in a fast scanning manner. Preferably, a fast scanning operation responsive to simultaneous depression of the two upward and downward scanning switches is stopped responsive to a receiving signal such as an intermediate frequency signal or a detected signal obtained when a broadcasting channel is selected. Preferably, a digital channel display is provided such that the data representative of the channel being selected obtainable from a control is transferred in a bit serial signal format to the display, wherein the pulses having a pulse width wider than a predetermined value are utilized for the purpose of data processing, thereby to eliminate any adverse affect due to noise during the transmission of the data.