Title:
FM RECEIVER
Document Type and Number:
Japanese Patent JP3288835
Kind Code:
B2
Abstract:
PURPOSE: To provide a demodulator for a PDM wave capable of interpolating missing pulses of PDM waves (pulse density modulation waves) and a demodulator for a PDM wave interpolating missing pulses in a weak electric field in an FM reception by the pulse count system so as to improve the sensitivity of the FM receiver.
CONSTITUTION: An FM wave is converted into a PDM wave by an amplitude limiter 3-a rectifier 6, the amplitude of the PDM wave is limited by an amplitude limit circuit 8 and the limited amplitude is inputted to both terminals of a convolver 10 via a convolver drive circuit 9. Then an output of the convolver 10 is decoded by a demodulation circuit 11, a large amplitude is extracted from an output pulse train by a slicer 12, a multivibrator(MV) circuit 13 generates a pulse with a minimum pulse interval τmin of the PDM wave to extract a level over a predetermined level in the convolver output, a slicer 12-a gate circuit 14 eliminate a pulse for a period of τmin from an output of the demodulation circuit 11 based on an output of a large amplitude part at the gate circuit 14, a limiter 15b makes the pulse amplitude constant to interpolate a missing pulse and provides an output and a low pass filter LPF 16 is used to decode the pulse as a base band signal 17.
Inventors:
Haruo Sakata
Application Number:
JP32630593A
Publication Date:
June 04, 2002
Filing Date:
November 30, 1993
Export Citation:
Assignee:
Clarion Co., Ltd.
International Classes:
H03D3/00; H03K9/06; H04B1/10; H04B1/26; (IPC1-7): H04B1/10; H03D3/00; H03K9/06; H04B1/26
Domestic Patent References:
| JP738336A | ||||
| JP730448A | ||||
| JP2283114A |
Attorney, Agent or Firm:
Busaburo Nagata
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