Radio receiver and method for suppressing attenuation properties of a low frequency signal

• US 6,112,069 A
• Filed: 01/15/1998
• Issued: 08/29/2000
• Est. Priority Date: 01/15/1997
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd. (Samsung Group)
• Original Assignee: Samsung Electronics Co. Ltd. (Samsung Group)
• Inventors: Na, Bo-Gyu
• Primary Examiner(s): TO, DORIS HA
• Application Number:
  US09/007,785
• Time in Patent Office: 957 Days
• Field of Search: 455/73, 455/75, 455/119, 455/255-256, 455/76, 455/84, 455/207, 455/205, 455/296, 455/312-316, 455/317-318, 331/34, 331/46, 331/182
• US Class Current: 455/296
• CPC Class Codes: H03D 7/166 using two or more quadrature frequency translation stages
• CPC Class Codes: H04B 1/30 for homodyne or synchrodyne receivers demodulator circuits H03D1/22

Abstract

A radio receiver, and a method therefore, for efficiently suppressing attenuation properties of a low frequency signal, in an analog frequency modulation type radio communication system. The radio receiver includes a first down-converter for mixing a modulated, high-frequency signal received by the radio receiver and a predetermined local oscillating signal to generate an intermediate frequency signal. A modulator modulates the predetermined local oscillating signal by an aural signal transmitted from the transmitter and generates a mixing signal for down-mixing the electrical signal representative of modulated, high-frequency signal. The mixed signal is then applied to the first down-converter. A second down-converter down-converts, in frequency, the intermediate frequency signal generated from the first down-converter into a baseband signal to generate the down-converted signal. A demodulator demodulates the down-converted baseband signal to a demodulated signal representative of the modulated, high-frequency signal received by the radio receiver.

Claims

1. A radio receiver in an analog frequency modulation type radio communication system including a receiver and a transmitter, said radio receiver comprising:

first means for down-converting in frequency an electrical signal representative of a modulated, high-frequency signal received by the radio receiver, said first down-converting means for mixing the modulated, high-frequency signal received by the radio receiver and a predetermined local oscillating signal, to generate an intermediate frequency signal;

means for modulating said predetermined local oscillating signal by an aural signal transmitted from the transmitter and generating a mixing signal for down-mixing the electrical signal representative of the modulated, high-frequency signal, to apply the mixing signal to said first down-converting means;

second means for down-converting in frequency the intermediate frequency signal generated from said first down-converting means into a baseband signal, to generate a down-converted baseband signal; and

means for converting the down-converted baseband signal into a demodulated signal representative of the modulated, high-frequency signal received by the radio receiver.

2. A radio receiver in an analog frequency modulation type radio communication System including a receiver and a transmitter, said radio receiver comprising:

first local oscillating means for generating a first local oscillating frequency signal, modulating the first local oscillating frequency signal by an aural signal transmitted from the transmitter, and supplying the modulated first local oscillating frequency signal to the receiver and the transmitter;

first means for down-converting in frequency an electrical signal representative of a modulated, high-frequency signal received by the radio receiver, said first down-converting means for mixing the modulated, high-frequency signal received by the radio receiver and the modulated first local oscillating frequency signal to generate a first intermediate frequency signal;

second local oscillating means for generating a second local oscillating frequency signal of an I-channel and a second local oscillating frequency signal of Q-channel;

third local oscillating means for generating a third local oscillating frequency signal of the I-channel and a third local oscillating frequency signal of the Q-channel;

second down-converting means for mixing the intermediate frequency signal and the second local oscillating frequency signal of an I-channel and the Q-channels, respectively, and down-converting the mixed signals to a second intermediate frequency signal of the baseband frequency of an I-channel and a second intermediate frequency signal of a baseband frequency of an Q-channel, to generate down-converted baseband signals;

third converting means for mixing the down-converted baseband signals of the I-channel and the Q-channel and the third local oscillating frequency signals of the I-channel and the Q-channel, respectively, and converting the mixed signals to a third intermediate frequency band signal of the I-channel and a third intermediate frequency band signal of the Q-channel, to generate converted signals; and

demodulation means for demodulating a third intermediate frequency signal in which the third intermediate frequency band signals of the I-channel the Q-channel are combined, and processing the modulated signal by an aural signal, to output the processed signal through a transducer to the outside.

3. The receiver according to claim 2 wherein said demodulation means further comprises:

a demodulator for demodulating the third intermediate frequency signal;

an audio processor for processing an output signal from the demodulator by a predetermined aural signal, and sending the processed signal through a speaker to the outside; and

means for eliminating an aural signal transmitted from the transmitter from components of an aural signal processed by said audio processor.

4. The receiver according to claim 3 wherein said means for eliminating generates a signal having an amplitude equal to the aural signal transmitted from the transmitter and an inverted phase.

5. In a radio receiver in an analog frequency modulation type radio communication system including a receiver and a transmitter, the radio receiver comprising a first down-converting means for mixing a modulated, high-frequency signal received by the radio receiver and a predetermined local oscillating signal to generate an intermediate frequency signal, a second means for down-converting, in frequency, the intermediate frequency signal generated from the first down-converting means into a baseband signal to generate a down-converted baseband signal, and a demodulator for demodulating the down-converted baseband signal into a demodulated signal representative of the modulated, high-frequency signal received by the radio receiver, a method for suppressing attenuation properties of a low frequency signal of signal components demodulated by said demodulator, said method comprising the steps of:

modulating said predetermined local oscillating signal by an aural signal transmitted from the transmitter; and

applying the modulated local oscillating signal to said first down-converting means.