Title:
RADIO RECEIVER
Document Type and Number:
Japanese Patent JPH08279831
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To actualize a direct converter demodulator which is adaptive to more than four input levels and used suitably in combination with an FSK receiver by equipping a demodulating device with a series-connection stage having a mixing circuit. SOLUTION: A demodulation stage 1 of a known type is coupled with a 2nd demodulation stage 2 and coupled with detectors 3 in order in the 2nd demodulation stage 2. Mixing circuits 3 and 4 to which radio signals are inputted are fed with even a signal of local oscillation of frequency Fc by a local oscillator 5. The signal of local oscillation that the mixing circuit 3 receives is shifted relatively in phase by 90 deg. from the signal of local oscillation received by the mixer 4 through a phase shifting circuit 6. The 2nd demodulation stage 2 has nearly the same two constitutions with constituent elements 3 to 6 of the 1st demodulation stage 1. Namely, one part of the 2nd demodulation stage 2 has two mixing circuits 11 and 12. Further, the other of the 2nd demodulation stage 2 also consists of two mixing circuits 15 and 16, a local oscillator 17 which operates at a frequency 2F, and a phase shifting circuit 18.
Inventors:
RODONII JIEIMUSU ROOTON
Application Number:
JP35021995A
Publication Date:
October 22, 1996
Filing Date:
December 22, 1995
Export Citation:
Assignee:
PLESSEY SEMICONDUCTORS LTD
International Classes:
H04L27/14; H04B1/06; H04L27/152; (IPC1-7): H04L27/14; H04B1/06
Attorney, Agent or Firm:
飯田 伸行