Phase locked loop demodulator with gain control
AssigneeDSP Group Switzerland AG
InventorsEric Desbonnets, Frédéric Parillaud, Erick Giroux
Life of this patent
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Abstract
The invention relates to a demodulator to demodulate frequency-modulated signals FM including a phase locked loop PLL including at least a phase detector, a loop filter and a voltage controlled oscillator function VCO′, characterized in that said voltage controlled oscillator function VCO′ has modifiable gain. The invention allows to eliminate drawbacks presented by the conventional use of a complex gain modifiable amplifier at the input of demodulated signal processing means. Application: demodulation of modulated signals: wireless phone, home network.
Claims5
A demodulator to demodulate frequency-modulated signals including a phase locked loop including at least a phase detector, a loop filter and a voltage controlled oscillator function VCO, characterized in that said voltage controlled oscillator function VCO has a modifiable gain, wherein the gain of said voltage controlled oscillator function VCO is modifiable using a programmable transconductance, and wherein the programmable transconductance includes a fixed transconductance, a current multiplier, the output of said programmable transconductance being the output of a summation unit that sums a combination of at least one output of said multiplier.
A method for demodulating frequency-modulated signals including the steps of:
- applying said frequency-modulated signals at the input of a phase locked loop including at least a phase detector, a loop filter and a voltage controlled oscillator function VCO,
- wherein the gain of said VCO is modifiable using a programmable transconductance, and wherein the programmable transconductance includes a fixed transconductance, a current multiplier, the output of said programmable transconductance being the output of a summation unit that sums a combination of at least one output of said multiplier, increasing frequency variations by increasing gain of the voltage controlled oscillator function VCO having a modifiable gain, producing demodulated signals at the output of said the phase locked loop.
Dependencies are inferred from the claim text.