JPS5752252A - Matching filter receiver - Google Patents

Abstract

PURPOSE:To reduce the cost price of a receiver, by constituting an automatic phase control APC loop for controlling so that the phase of a local oscillation signal coincides with that of a receiving signal, and controlling a voltage controlling oscillator VCO. CONSTITUTION:An APC loop for controlling so that the phase of a carrier wave generated by a local oscillator, appearing in an output of a phase shifter 14 coincides with the phase of a carrier wave of an inut signal is constituted of mixers 2e, 2f, matching filters 3e, 3f, square-law detectors 4e, 4f, a subtracter 11, an LPF 12, a VCO 13 and a phase shifter 10. 2 channel signals which have passed through the mixers of a receiving signal applied to a terminal 1, and have been detected at the square-law detector control the VCO 13 through the subtracter 11 and the LPF 12, apply a signal of the VCO 13 to a mixer 2g through the phase shifter 14, decide its output by a deciding device 15 through a matching filter 3g, and provide a demodulated data. since a signal to which APC has been executed is applied to the mixer 2g, an ideal coherent detection is executed. Moreover, since the number of matching filters is only three, the cost price is reduced.