Title:
FREQUENCY MODULATOR
Document Type and Number:
Japanese Patent JPH01165209
Kind Code:
A
Abstract:
PURPOSE:To perform the adjustment of a central frequency and that of deviation by simultaneous adjustment by the same voltage by using three gm amplifiers and four current sources. CONSTITUTION:A first current source controls the gm of a first gm amplifier to which a control voltage with the central frequency fo is supplied, and a third current source controls the gm of a third gm amplifier to which a control voltage with modulation sensitivity (deviation) is supplied, and the sum of output currents of a second current source and the above stated third gm amplifier controls the gm of a second gm amplifier. The sum current of the output current of the first gm amplifier which sets a fo control voltage as input and that of the second gm amplifier which sets a modulation signal as the input and the current of a fourth current source goes to the control current of a multivibrator. And by setting a current ratio of the first current source to the fourth current source so as to be established in prescribed relation, it is possible to perform the adjustment of the frequency fo and that of the deviation by the same voltage(simultaneous adjustment).
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Inventors:
YAMAMOTO TAKESHI
Application Number:
JP32308787A
Publication Date:
June 29, 1989
Filing Date:
December 21, 1987
Export Citation:
Assignee:
TOSHIBA CORP
International Classes:
H03L1/00; H03F3/00; (IPC1-7): H03F3/00; H03L1/00
Attorney, Agent or Firm:
Takehiko Suzue (2 outside)