Wide band radio receiver

• US 4,627,100 A
• Filed: 12/28/1984
• Issued: 12/02/1986
• Est. Priority Date: 12/28/1984
• Status: Expired due to Term

• Current Assignee: UJB Financial Corp. (New Jersey) (Bank of America Corp.)
• Original Assignee: Regency Electronics Incorporated (BK Technologies Corp.)
• Inventors: Takano, Shigeru
• Primary Examiner(s): NG, Jin F.
• Application Number:
  US06/687,191
• Time in Patent Office: 704 Days
• Field of Search: 455/160, 455/165, 455/168, 455/183, 455/189, 455/207, 455/209, 455/315, 455/316
• US Class Current: 455/160.1
• CPC Class Codes: H03B 21/02 by plural beating, i.e. for frequency synthesis ; Beating in combination with multiplication or division of frequency digital frequency synthesis using a ROM G06F1/02; digital frequency synthesis in general H03K; indirect frequency synthesis using a PLL H03L7/16
• CPC Class Codes: H03D 7/161 all the frequency changers being connected in cascade
• CPC Class Codes: H03J 5/0281 the digital values being held in an auxiliary non erasable memory

Abstract

A circuit arrangement for a wide band superheterodyne radio receiver for receiving wide band FM, narrow band FM, and AM modulated radio signals between 25 and 550 MHz. The first LO is a phase locked loop controlled VCO, with central processing unit control of the phase locked loop circuitry. The first IF frequency is higher than the highest received frequency and the output frequency of the first LO is higher than the first IF. A second LO and second mixer convert the signal to a second IF lower than the first IF. Separate third and fourth IF band pass filters are provided at the second IF for WFM and for NFM/AM, respectively. The output of the third IF filter (WFM) is converted by a third LO and third mixer to a third IF lower than the second IF. A WFM demodulator is provided at the third IF. The output of the fourth IF filter (NFM/AM) is converted by a fourth LO and fourth mixer to a fourth IF lower than the second IF frequency. A fifth IF band pass filter is provided at the fourth IF. The output of the fifth IF filter is received be separate NFM and AM demodulators. Each demodulator is followed by its own audio amplifier, each selectively connectable to a speaker.

Claims

1. A superheterodyne radio receiver, comprising:

a synthesized first local oscillator for producing a signal having a frequency which is variable between about 775 MHz to about 1300 MHz, said first local oscillator being varactor tuned;

phase locked loop circuitry means for controlling the frequency of the signal produced by said synthesized first local oscillator;

central processing computer means for controlling said phase locked loop circuitry in response to data entered from manually operable keypad switches;

a first mixer circuit for converting an incoming received signal having a frequency within the band of about 25 to about 550 MHz to a first intermediate frequency signal of about 750 MHz by mixing said incoming received signal with the signal from said first local oscillator;

a filter circuit centered about 750 MHz for selectively receiving said first intermediate frequency signal;

a second local oscillator for producing a signal having a frequency of about 704.97 MHz;

a second mixer circuit for converting said filtered first intermediate frequency signal to a second intermediate frequency signal of about 45.0275 MHz by mixing said filtered first intermediate frequency signal with the signal from said second local oscillator;

a wide band FM filter circuit centered about 45.0275 MHz for selectively receiving said second intermediate frequency signal;

a third local oscillator for producing a signal having a frequency of about 39.53 MHz;

a third mixing circuit for converting said filtered second intermediate frequency signal to a third intermediate frequency signal of about 5.5 MHz by mixing said filtered second intermediate frequency signal with the signal from said third local oscillator;

a filter circuit centered about 5.5 MHz for selectively receiving said third intermediate frequency signal;

wide band FM detector means for receiving said filtered third intermediate frequency signal and detecting wide band FM audio modulation thereof, and outputing the detected modulation as an audio frequency signal;

a narrow band FM and AM crystal filter circuit centered about 45.0275 MHz for selectively receiving said second intermediate frequency signal;

a fourth local oscillator for producing a signal having a frequency selectively switchable between about 44.575 MHz and about 44.570 MHz;

a fourth mixing circuit for converting said crystal filtered second intermediate frequency signal to a fourth intermediate frequency signal of about 452.5 kHz to about 457.5 kHz by mixing said crystal filtered second intermediate frequency signal with the signal from said fourth local oscillator;

a filter circuit centered about 455 kHz for selectively receiving said fourth intermediate frequency signal;

narrow band FM detector means for receiving said filtered fourth intermediate frequency signal and detecting narrow band FM audio modulation thereof, and outputting the detected modulation as an audio frequency signal;

AM detector means for receiving said filtered fourth intermediate frequency signal and detecting AM audio modulation thereof, and outputting the detected modulation as an audio frequency signal;

first mode switching means for selectively directing said second intermediate frequency signal to;

(a) said wide band FM filter circuit, or

(b) said narrow band FM and AM crystal filter circuit;

second mode switching means for selectively rendering inoperable any two of said wide band FM detector means, said narrow band FM detector means, and said AM detector means;

pass-band-shift switching means for selectively switching the frequency produced by said fourth local oscillator;

an audio amplifier for receiving and amplifying the output audio frequency signal from said wide band FM detector;

an audio amplifier for receiving and amplifying the output audio frequency signal from said narrow band FM detector;

an audio amplifier for receiving and amplifying the output audio frequency signal from said AM detector; and

a speaker selectively connectable to any one of said audio amplifiers for audibly reproducing the audio frequency signal therefrom.

2. A circuit arrangement for a wide band superheterodyne radio receiver for receiving incoming radio signals between about 25 MHz and 550 MHz, comprising:

a variable first local oscillator for producing an output signal having a variable frequency higher than the upper frequency limit of said incoming radio signals;

a first mixer resonsive to said incoming radio signals and to the output signal of said first local oscillator for converting said incoming radio signals to a first intermediate frequency which is higher than the upper frequency limit of said incoming radio signals and which is higher than about 550 MHz;

a first intermediate frequency bandpass filter circuit selectively responsive to said first intermediate frequency;

a second local oscillator;

a second mixer responsive to the output signal of said first intermediate frequency filter circuit and to the output signal of said second local oscillator for converting the output signal of said first intermediate frequency filter circuit to a second intermediate frequency signal which is lower in frequency than said first intermediate frequency signal;

a second intermediate frequency band pass filter circuit selectively responsive to said second intermediate frequency signal;

a third local oscillator;

a third mixer responsive to the output signal of said second intermediate frequency filter circuit and to the output signal of said third local oscillator for converting the output signal of said second intermediate frequency filter circuit to a third intermediate frequency signal which is lower in frequency than said second intermediate frequency signal;

a third intermediate frequency band pass filter circuit selectively responsive to said third intermediate frequency signal;

first FM demodulator means for receiving the output signal of said third intermediate frequency filter circuit and demodulating FM audio modulation thereof, and outputing the demodulated signal as an audio frequency signal;

a fourth intermediate frequency band pass filter circuit selectively responsive to said second intermediate frequency signal and having a bandwidth narrower than the bandwidth of said second intermediate band pass filter circuit;

a fourth local oscillator;

a fourth mixer responsive to the output signal of said fourth intermediate frequency filter circuit and to the output signal of said local oscillator for converting the output signal of said fourth intermediate frequency filter circuit to a fourth intermediate frequency signal which is lower in frequency than said second intermediate frequency signal;

a fifth intermediate frequency band pass filter circuit selectively responsive to said fourth intermediate frequency signal;

second FM demodulator means for receiving the output signal of said fifth intermediate frequency filter circuit and demodulating FM audio modulation thereof, and outputing the demodulated signal as an audio frequency signal; and

phase locked loop circuitry means for controlling the frequency of said first local oscillator; and

controller means responsive to externally manipulable switches for controlling said phase locked loop circuitry means to provide manual frequency tuning and automatic frequency scanning of said incoming radio signals.

3. The circuit arrangement of claim 2, and further including:

AM demodulator means for receiving the output signal of said fifth intermediate frequency filter circuit and demodulating AM audio modulation thereof, and outputting the demodulated signal as an audio frequency signal.

4. The circuit arrangement of claim 3, and further including:

first mode switching means for selectively directing said second intermediate frequency signal to;

(a) said third intermediate frequency band pass filter circuit, or

(b) said fourth intermediate frequency band pass filter circuit.

5. The circuit arrangement of claim 4, and further including:

second mode switching means for selectively rendering inoperable any two of said first FM demodulator means, said second FM demodulator means, and said AM demodulator means.

6. The circuit arrangement of claim 5, and further including:

pass-band-shift switching means for selectively switching the frequency produced by said fourth local oscillator.