Title:
TUNING-CONTROL SYSTEM
Document Type and Number:
Japanese Patent JP3798078
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide a tuning-control system which is suitable for a circuit integration and is easily turned to a desired tuning frequency, even in the case that the system is in an integrated circuit.
SOLUTION: An input signal to be given to a tuning circuit 1 is interrupted, just after a tuning device has started or just after a turning frequency has been switched, and a loop gain of a feedback loop of the tuning circuit 1 is set to be unity or over. Then the tuning circuit 1 makes an oscillation at a prescribed frequency, based on a control signal in response to an output of a PLL control circuit 3. When a desired tuning frequency is stably set to the tuning circuit 1, an external input signal is given to the tuning circuit 1, and the loop gain of the feedback loop is set to be less than unity. Then the tuning circuit 1 conducts the turning operation based on the control signal, in response to a phase difference between the input signal and an output signal, and thereafter, the tuning frequency is controlled so as to match with the frequency of the input signal.
Inventors:
Akira Okamoto
Takeshi Ikeda
Takeshi Ikeda
Application Number:
JP21657996A
Publication Date:
July 19, 2006
Filing Date:
July 30, 1996
Export Citation:
Assignee:
NIIGATA SEIMITSU CO.,LTD.
International Classes:
H03F3/191; H03J3/10; H03J3/06; H03J7/02; (IPC1-7): H03J7/02; H03F3/191; H03J3/06
Domestic Patent References:
| JP4138711A |
Attorney, Agent or Firm:
Masahiko Amagai