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    VARIABLE FREQUENCY U.H.F. LOCAL OSCILLATOR FOR A TELEVISION RECEIVER
    44.
    发明专利
    VARIABLE FREQUENCY U.H.F. LOCAL OSCILLATOR FOR A TELEVISION RECEIVER 未知

    公开(公告)号：CA1204175A

    公开(公告)日：1986-05-06

    申请号：CA426796

    申请日：1983-04-27

    Applicant: RCA CORP

    Inventor： LEA JEFFREY G ,  CARLSON DAVID J

    IPC: H04N5/44 ,  H03B1/00 ,  H03B5/12 ,  H04B1/26 ,  H03J3/20

    Abstract: A tunable oscillator develops a signal having a frequency variable over a range of frequencies in response to a control signal. A frequency determining resonant circuit includes two voltage-variable capacitance diodes in an arrangement for adjusting at least one endpoint of the frequency range. As a result, the relationship between the magnitude of the control signal and the freguency of the oscillator signal can be adjusted while avoiding mechanically adjustable reactive elements. The disclosed arrangement is suitably employed with resonant circuits other than those in oscillators.

    PHASE LOCKED LOOP TUNING SYSTEM INCLUDING A PRESCALER CONDITIONED TO OSCILLATE AT AN OUT-OF-BAND FREQUENCY
    45.
    发明专利
    PHASE LOCKED LOOP TUNING SYSTEM INCLUDING A PRESCALER CONDITIONED TO OSCILLATE AT AN OUT-OF-BAND FREQUENCY 未知

    公开(公告)号：CA1175491A

    公开(公告)日：1984-10-02

    申请号：CA404100

    申请日：1982-05-31

    Applicant: RCA CORP

    Inventor： CARLSON DAVID J ,  LEHMANN WILLIAM L

    IPC: H03J7/28 ,  H03J5/02 ,  H03L7/00 ,  H03L7/193 ,  H04B1/10 ,  H04B1/26 ,  H03J5/00

    Abstract: RCA 77,180 In a phase locked loop tuning system including a prescaler for dividing the frequency of the local oscillator signal by a factor selected to make the resultant frequency divided signal compatible with digital processing portions of the tuning system, a frequency selective network is coupled to the prescaler to tune the self-oscillation frequency of the prescaler to a frequency not corresponding to the local oscillator frequency of any legitimate channel. In this manner, when a new channel is selected and the amplitude of the local oscillator signal is below the threshold at which the prescaler will respond to it, the phase locked loop will properly control the local oscillator, rather than respond to a self-oscillation signal which may otherwise correspond to the local oscillator frequency for the selected channel.

    OSCILLATOR SIGNAL AMPLITUDE COMPENSATION MEANS
    46.
    发明专利
    OSCILLATOR SIGNAL AMPLITUDE COMPENSATION MEANS 未知

    公开(公告)号：CA1000813A

    公开(公告)日：1976-11-30

    申请号：CA207032

    申请日：1974-08-14

    Applicant: RCA CORP

    Inventor： CARLSON DAVID J

    IPC: H03B5/04 ,  H03B1/00 ,  H03B5/18

    Abstract: A voltage-dependent capacitor tuned oscillator employs a diode as a coupling element between an amplifying device and a resonant circuit to provide a feedback signal to the amplifying device required to sustain oscillations. The diode further provides charging current for a capacitor in the resonant circuit when a first polarity portion of the oscillations increase above a predetermined level. The charge on the capacitor decreases the feedback level, thus stabilizing the level of oscillations in the resonant circuit for each frequency to which the oscillator is tuned.

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