Title:
METHOD AND EQUIPMENT FOR SETTING SELF-RUNNING OSCILLATION FREQUENCY OF VOLTAGE CONTROLLED OSCILLAOR OF PLL CIRCUIT
Document Type and Number:
Japanese Patent JPH0329516
Kind Code:
A
Abstract:
PURPOSE: To set the free-running oscillation frequency of the VCO of a phase locked loop(PLL) circuit by incrementing or decrementing the output frequency of a voltage controlled oscillator(VCO) according to the size of a count value stored in a register and an expected count value. CONSTITUTION: A comparator 34 compares an actual count value M of a VCO output pulse stored in a register 35 with an expected count value R of the preset VCO output pulse in response to the previous strobe pulse when conditioned by a strobe pulse. Then, when MR, it decrements the counter 32. Thus, it is not necessary to operate the laser trimming of a VCO 12 for setting a VCO free-running oscillation frequency, and the free- running oscillation frequency of the VCO 12 is held in the lock range of a phase locked loop(PLL) circuit.
Inventors:
POORU UISHINGU CHIYONGU
RARUFU REONAADO JII
RIYUUKU CHIYONGU KUWANGU RANGU
POOKU SABAA
RARUFU REONAADO JII
RIYUUKU CHIYONGU KUWANGU RANGU
POOKU SABAA
Application Number:
JP14641390A
Publication Date:
February 07, 1991
Filing Date:
June 06, 1990
Export Citation:
Assignee:
IBM
International Classes:
H03L7/113; G11B20/14; H03L7/14; G11B20/12; (IPC1-7): G11B20/14; H03L7/14
Domestic Patent References:
| JPS6247240B2 | 1987-10-07 | |||
| JPS4979151A | 1974-07-31 | |||
| JPS5676636A | 1981-06-24 | |||
| JPS62296623A | 1987-12-23 |
Attorney, Agent or Firm:
Jiro Yamamoto (1 person outside)
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