초록 ▼

A system and method using a Costas loop to effect accelerated convergence with minimal system complexity. The system comprises an in-phase-limiter and a quadrature-phase limiter, operatively coupled to an EXCLUSIVE-OR gate, for exclusively-ORing an in-phase-sign signal and a quadrature-phase-sign si

A system and method using a Costas loop to effect accelerated convergence with minimal system complexity. The system comprises an in-phase-limiter and a quadrature-phase limiter, operatively coupled to an EXCLUSIVE-OR gate, for exclusively-ORing an in-phase-sign signal and a quadrature-phase-sign signal to output a first error signal, responsive to the signals having same signs, or a second error signal, responsive to the signals having different signs. An AGC circuit, operatively coupled to an output of the EXCLUSIVE-OR gate, increases and decreases a voltage level of an AGC signal responsive to two consecutive first or second error signals and consecutive dissimilar error signals, respectively. A voltage-controlled oscillator, operatively coupled to an output of the AGC circuit and responsive to the increased or decreased voltage level, changes the frequency of a voltage-controlled-oscillator output signal.

대표청구항 ▼

[ I claim:] [1.] An adaptive gain control subsystem for use with a Costas loop, comprising:first generating means for generating an in-phase-sign signal from an in-phase portion of a despread spread-spectrum signal;second generating means for generating a quadrature-phase-sign signal from a quadratu

[ I claim:] [1.] An adaptive gain control subsystem for use with a Costas loop, comprising:first generating means for generating an in-phase-sign signal from an in-phase portion of a despread spread-spectrum signal;second generating means for generating a quadrature-phase-sign signal from a quadrature-phase portion of the despread spread-spectrum signal;third generating means, operatively coupled to said first generating means and to said second generating means, responsive to the in-phase-sign signal and to the quadrature-phase-sign signal having same signs, for outputting a first error signal;an adaptive-gain-control (AGC) amplifier, having a gain, operatively coupled to said third generating means, for amplifying the first error signal;a register, operatively coupled to an output of said third generating means, for storing a first previous error signal from said third generating means, with the first previous error signal previously occurring in time with respect to the first error signal;an EXCLUSIVE-NOR gate, having a first input operatively coupled to an output of said third generating means, a second input operatively coupled to an output of said register, responsive to the first error signal from said third generating means and the first previous error signal stored in said register, having a same value, for outputting a first value, and responsive to the first error signal from said third generating means and the first previous error signal stored in said register, having a different value, for outputting a second value;averaging means, coupled between said EXCLUSIVE-NOR gate and said AGC amplifier, for averaging a plurality of first values and second values, thereby generating a first averaged value; andsaid AGC amplifier, responsive to the first averaged value increasing, for increasing the gain of said AGC amplifier, said AGC amplifier, responsive to the first averaged value decreasing, for decreasing the gain of said AGC amplifier.