Linear gain voltage controlled oscillator with modulation compensation
AssigneeMotorola, Inc.
InventorsCraig W. Rice, Marc H. Popek
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Abstract
In a compensated VCO circuit arrangement for providing constant modulation level over a wide frequency band a VCO is disclosed having a linear VCO gain factor vs. control voltage curve over the wide frequency band of interest. A compensation network is coupled to the VCO to provide an audio output having a linear output level vs. control voltage curve. By appropriately matching the two linear curves the variation in modulation level over the frequency band of interest is substantially reduced.
Claims9
A compensated voltage controlled oscillator arrangement for providing a substantially constant modulation level over a wide frequency band, comprising:
- a linear gain voltage controlled oscillator (VCO) having a control input and responsive to a control voltage for providing a substantially constant change in VCO gain factor K.sub.0 for a fixed change in said control voltage over a predetermined range of frequencies;
- input means for receiving an input modulating signal;
- and
- linear compensation means, coupled to said input means and said control input of said voltage controlled oscillator and responsive to said control voltage for providing a compensated output signal to said contol input of said VCO having a substantially constant change in signal level for a fixed change in said control voltage over said predetermined range of frequencies, so that the product of said compensated output signal and said VCO gain factor K.sub.0 is substantially constant over said predetermined range of frequencies.
Dependencies are inferred from the claim text.