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    SIGNAL INTERFERENCE PROTECTION CIRCUIT FOR AM STEREO RECEIVER
    12.
    发明专利
    SIGNAL INTERFERENCE PROTECTION CIRCUIT FOR AM STEREO RECEIVER 未知

    公开(公告)号：CA1196387A

    公开(公告)日：1985-11-05

    申请号：CA429897

    申请日：1983-06-07

    Applicant: MOTOROLA INC

    Inventor： ECKLUND LAWRENCE M ,  ESPE ROY H

    IPC: H04H1/00 ,  H04H40/36 ,  H04H20/49 ,  H04H20/88 ,  H04H40/45 ,  H04M5/00 ,  H04H5/00 ,  H04B1/16

    Abstract: In the field of AM stereo detection, co-channel or adjacent channel interference may cause some distortion and side-to-side movement of a stereo signal source as well as false "stereo detect" signals in AM stereo receivers having phase locked loop (PLL) systems. The invention provides a filter receiving the incoming signal and passing only the frequencies resulting from said interference; a sensor measures the output of the filters and if this signal is above a given level, the monophonic mode is enabled, i.e., the pilot detector, the stereo presence indicator and the stereo mode switch are disenabled for a timed interval. A higher given level of interference is required for stereo disenablement when stereo transmission with pilot tone is already being received.

    PILOT TONE DETECTOR UTILIZING PHASE DEVIATION SIGNALS
    13.
    发明专利
    PILOT TONE DETECTOR UTILIZING PHASE DEVIATION SIGNALS 未知

    公开(公告)号：CA1166317A

    公开(公告)日：1984-04-24

    申请号：CA397697

    申请日：1982-03-05

    Applicant: MOTOROLA INC

    Inventor： ECKLUND LAWRENCE M ,  DRONG FRANK JR

    IPC: H04H1/00 ,  H04H20/49 ,  H04B1/16

    Abstract: An AM stereophonic pilot tone is detected using two signals derived from a received broadcast signal. One signal is proportional to the phase deviation and one is a two-level signal which is a function of the magnitude of the phase deviation. The detector controls activation of the visual indicator, muting of the stereo channel of mono/stereo mode switching with almost complete elimination of false detections during monophonic transmission and poor stereo transmission.

    14.
    发明专利
    未知

    公开(公告)号：DE68922006T2

    公开(公告)日：1995-10-26

    申请号：DE68922006

    申请日：1989-01-26

    Applicant: MOTOROLA INC

    Inventor： ESPE ROY H ,  ECKLUND LAWRENCE M

    IPC: H03L7/18 ,  H03L7/093 ,  H03L7/10 ,  H03L7/113

    Abstract: There is disclosed a circuit (60) responsive to control signals applied thereto for alternatively sourcing and sinking current at an output which includes a first controlled current source (48) responsive to selective ones of the control signals for sourcing a current of a predetermined magnitude to the output of the circuit; a second controlled current source (50) responsive to other selective ones of the control signals for sinking a current of a predetermined magnitude from the output of the circuit; and a disabling circuit (42, 44) for respectively disabling said first and second controlled current sources whenever the voltage potential at the output of the circuit becomes greater or less than a predetermined value respectively.

    AM-FM COMBINED STEREO RECEIVER
    16.
    发明专利
    AM-FM COMBINED STEREO RECEIVER 未知

    公开(公告)号：CA2100447A1

    公开(公告)日：1992-08-07

    申请号：CA2100447

    申请日：1992-02-04

    Applicant: MOTOROLA INC

    Inventor： ECKLUND LAWRENCE M

    IPC: H03D3/24 ,  H03D5/00 ,  H04B1/06 ,  H04B1/16 ,  H04H20/88

    Abstract: 2100447 9214299 PCTABS00014 An improved AM-FM combined stereo receiver (100) is provided having a single processor (155) for removing, in the FM mode, arc-tangent distortion, and in the AM mode, to process the phase term from arc-tangent L - R/1 + L + R to determine L - R/1 + L + R . Further, the radio includes a single discriminator circuit (161, 137, 139) wherein, in the FM mode, the discriminator tank circuit (137, 139) is used to convert frequency deviation to baseband audio and, in the AM mode, the discriminator tank circuit is used as the frequency-determining element for the voltage controlled oscillator (VCO) (161), the VCO being used to translate the intermediate frequency (IF) signal to baseband.

    DUAL INDICATOR CIRCUIT FOR TUNING AND STEREO SIGNALS
    18.
    发明专利
    DUAL INDICATOR CIRCUIT FOR TUNING AND STEREO SIGNALS 未知

    公开(公告)号：HK33190A

    公开(公告)日：1990-05-11

    申请号：HK33190

    申请日：1990-05-03

    Applicant: MOTOROLA INC

    Inventor： ECKLUND LAWRENCE M

    IPC: H04B1/16 ,  H03J3/14 ,  H04H20/88 ,  H04S7/00

    Abstract: In a stereophonic broadcasting receiver, a single indicator with two levels of illumination serves to provide indication of both accurate tuning and the presence of stereophonic signals. One signal or a combination of signals related to the tuning circuits of the receiver cause the indicator to be illuminated to a perceptible level. When, by use of a pilot tone detector, it is certain that stereophonic signals are being received, additional current is caused to flow through the indicator, raising the illumination to the maximum allowable level. The circuit has particular application to manually tuned receivers.

    BROADCAST SIGNAL DETECTED INDICATION SYSTEM
    19.
    发明专利
    BROADCAST SIGNAL DETECTED INDICATION SYSTEM 未知

    公开(公告)号：AU7780587A

    公开(公告)日：1988-03-24

    申请号：AU7780587

    申请日：1987-07-20

    Applicant: MOTOROLA INC

    Inventor： ECKLUND LAWRENCE M

    IPC: H03J5/00 ,  H03J7/18 ,  H04H20/88 ,  H04H5/00

    Abstract: In a radio having an in phase multiplier (A) for providing an in phase detected signal, a detection unit for receiving this signal and for determining whether this signal includes any negative polarity components which would indicate that a viable broadcast signal does not exist on the incoming frequency of interest. This detection unit can include a comparator (11) for comparing the incoming signal against a selected reference value. The invention can also include a signal quality evaluation unit (58) for providing either a digital or analog quality signal that can also effect the output and be used by appropriate processing circuitry to further refine the channel selection process.

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