EP0470089A4 - Receiver threshold extension - Google Patents

Receiver threshold extension

Info

Publication number
EP0470089A4
EP0470089A4 EP19900905988 EP90905988A EP0470089A4 EP 0470089 A4 EP0470089 A4 EP 0470089A4 EP 19900905988 EP19900905988 EP 19900905988 EP 90905988 A EP90905988 A EP 90905988A EP 0470089 A4 EP0470089 A4 EP 0470089A4
Authority
EP
European Patent Office
Prior art keywords
signal
receiver
unmodulated
received
threshold
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP19900905988
Other languages
English (en)
Other versions
EP0470089A1 (fr
Inventor
Robert E. Stengel
Paul David Marko
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Motorola Solutions Inc
Original Assignee
Motorola Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Motorola Inc filed Critical Motorola Inc
Publication of EP0470089A1 publication Critical patent/EP0470089A1/fr
Publication of EP0470089A4 publication Critical patent/EP0470089A4/en
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/06—Receivers
    • H04B1/10—Means associated with receiver for limiting or suppressing noise or interference

Definitions

  • This invention relates generally to radio frequency receivers and more particularly to receivers with sensitivity improvement.
  • One measure of a receiver's performance is its ability to reject noise while providing a clear desired signal. Typically, this performance is rated by a signal-to-noise ratio. The higher the signal-to-noise ratio, the better the sensitivity (and performance) of the receiver.
  • an information signal is received and examined to determine its signal strength.
  • the signal strength is at least equal to a threshold, an unmodulated signal is added to the received signal to improve 0 the sensitivity of the receiver.
  • FIG. 1 is a block diagram of a receiver in accordance with the present invention. 5
  • a receiver 10 having an information signal 11 being received by an antenna 12.
  • the received information signal (and received noise) is filtered 0 (bandlimited) via a preselector 14 before being mixed (mixer 16) with an injection signal from an oscillator 18.
  • the oscillator 18 is programmed (34) to provide a suitable injection signal by a controller 32 so that a desired information signal can be received.
  • the mixer 16 provides an intermediate frequency (IF) signal to an 5 IF amplifier 20 to be amplified prior to being filtered by an IF filter 22.
  • the filtered signal is processed by a detector 24 to provide a recovered signal. It will be appreciated that an additional intermediate frequency stage can be added before the mixer 16 along with additional bandpass filters.
  • the detected or recovered fj signal is amplified in an optional audio amplifier 26 before being presented via a speaker 28.
  • the signal strength of the desired received IF signal is determined and compared to a threshold.
  • signal strength detection is accomplished in the IF amplifier 20, which has a receiver signal strength indicator (RSSI) output.
  • the IF amplifier 20 comprises an MC 3362 manufactured by Motorola Inc. or its functional equivalent.
  • the present invention adds an unmodulated signal to the received IF signal when the received IF signal is below a predetermined threshold (which may be set at the 3dB signal-to- noise ratio). If the RSSI output (30) indicates that the received IF signal is at or below the threshold (set near the noise level), the controller 32 programs (42) the frequency of another oscillator 40 to produce the unmodulated signal. Having its frequency set at the same frequency of the received IF signal, the unmodulated signal is amplified in an amplifier 38 controlled by the controller 32 (via line 36) before being added (summed 39) to the received IF signal at the input to the filter 22.
  • a predetermined threshold which may be set at the 3dB signal-to- noise ratio
  • the gain of the amplifier 38 is set (36) such that the amplitude of the unmodulated carrier signal is preferably at least 8dB above the threshold (which is set near the noise level). It will be appreciated that the summing node 39 may occur before or after the filter 22.
EP19900905988 1989-04-26 1990-04-09 Receiver threshold extension Withdrawn EP0470089A4 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US34332089A 1989-04-26 1989-04-26
US343320 1989-04-26

Publications (2)

Publication Number Publication Date
EP0470089A1 EP0470089A1 (fr) 1992-02-12
EP0470089A4 true EP0470089A4 (en) 1992-09-16

Family

ID=23345613

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19900905988 Withdrawn EP0470089A4 (en) 1989-04-26 1990-04-09 Receiver threshold extension

Country Status (3)

Country Link
EP (1) EP0470089A4 (fr)
JP (1) JPH04504935A (fr)
WO (1) WO1990013188A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10024375A1 (de) * 2000-05-17 2001-12-20 Infineon Technologies Ag Vermeidung eines Störzustandes

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3588705A (en) * 1969-11-12 1971-06-28 Nasa Frequency-modulation demodulator threshold extension device
US3983488A (en) * 1974-06-17 1976-09-28 California Microwave, Inc. Frequency-modulation demodulator threshold extension device
FR2452208A1 (fr) * 1979-03-20 1980-10-17 Thomson Csf Tete h.f. a dynamique autoadaptative et recepteur comportant une telle tete h.f.
JPS56147525A (en) * 1980-04-18 1981-11-16 Hitachi Ltd Reception playback system
US4672632A (en) * 1984-02-03 1987-06-09 Motorola, Inc. Optimized communications system and method employing channel synthesis and phase lock detection
JPS645121A (en) * 1987-06-27 1989-01-10 Tokyo Gas Co Ltd Noise suppression device for fm transmitter-receiver

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 13, no. 176 (E-749)(3524) 25 April 1989 & JP-A-1 005 121 ( TOKYO GAS CO ) *
See also references of WO9013188A1 *

Also Published As

Publication number Publication date
WO1990013188A1 (fr) 1990-11-01
EP0470089A1 (fr) 1992-02-12
JPH04504935A (ja) 1992-08-27

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Legal Events

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