Coherent detection using matched filter enhanced spread spectrum demodulation

A spread-spectrum-phase-locked-loop apparatus, for use as part of a spread-spectrum receiver on a received-spread-spectrum signal generated from spread-spectrum processing a symbol-sequence signal with a chip-sequence signal, comprising:

• in-phase-symbol-matched means, responsive to having an in-phase-symbol-impulse response matched to the chip-sequence signal, for despreading from the received-spread-spectrum signal, an in-phase component as a despread-in-phase component of a symbol-sequence signal;
• quadrature-phase-symbol-matched means, responsive to having a quadrature-symbol-impulse response matched to the chip-sequence signal, for despreading from the received-spread-spectrum signal, a quadrature-phase component as a despread-quadrature-phase component of the symbol-sequence signal;
• a voltage-controlled oscillator (VCO), coupled to said in-phase-symbol-matched means and to said quadrature-phase-symbol-matched means, for generating a VCO-sine signal and a VCO-cosine signal, with the VCO-cosine signal having a phase 90.degree. from the VCO-sine signal;
• first product means, coupled to said in-phase-symbol-matched means and to said voltage-controlled oscillator, for multiplying the despread-in-phase component of the symbol-sequence signal by the VCO-cosine signal, thereby generating a first product signal;
• second product means, coupled to said in-phase-symbol-matched means and to said voltage-controlled oscillator, for multiplying the despread-in-phase component of the symbol-sequence signal by the VCO-cosine signal, thereby generating a first product signal;
• second product means, coupled to said in-phase-symbol-matched means and to said voltage-controlled oscillator, for multiplying the despread-in-phase component of the symbol-sequence signal by the VCO-sine signal, thereby generating a second product signal;
• third product means, coupled to said quadrature-phase-symbol-matched means and to said voltage-controlled oscillator, for multiplying the despread-quadrature-phase component of the symbol-sequence signal by the VCO-sine signal, thereby generating a third product signal;
• fourth product means, coupled to said quadrature-phase-symbol-matched means and to said voltage-controlled oscillator, for multiplying the despread-quadrature-phase component of the symbol-sequence signal by the VCO-cosine signal, thereby generating a fourth product signal;
• first combining means, coupled to said first product means and to said third product means, for combining the first product signal with the third product signal, thereby generating a first combined signal;
• second combining means, coupled to said second product means and to said fourth product means, for combining the second product signal with the fourth product signal, thereby generating a second combining signal;
• fifth product means, coupled to said first combining means and to said second combining means, for multiplying the first combined signal by the second combined signal, thereby generating an error signal;
• and
• wherein said voltage-controlled oscillator, responsive to the error signal, adjusts a level of the VCO-sine signal and a level of the VCO-cosine signal.

A spread-spectrum-phase-locked-loop method, for use as part of a spread-spectrum receiver on a received-spread-spectrum signal generated from spread-spectrum processing a symbol-sequence signal with a chip-sequence signal, comprising:

• despreading, from the received-spread-spectrum signal, an in-phase component as a despread-in-phase component of the symbol-sequence signal;
• despreading, from the received-spread-spectrum signal, a quadrature-phase component as a despread-quadrature-phase component of the symbol-sequence signal;
• generating, from a voltage-controlled oscillator (VCO), a VCO-sine signal and a VCO-cosine signal, with the VCO-cosine signal having a phase 90.degree. from the VCO-sine signal;
• multiplying the despread-in-phase component of the symbol-sequence signal by the VCO-cosine signal, thereby generating a first product signal;
• multiplying the despread-in-phase component of the symbol-sequence signal by the VCO-sine signal, thereby generating a second product signal;
• multiplying the despread-quadrature-phase component of the symbol-sequence signal by the VCO-sine signal, thereby generating a third product signal;
• multiplying the despread-quadrature-phase component of the symbol-sequence signal by the VCO-cosine signal, thereby generating a fourth product signal;
• combining the first product signal with the third product signal, thereby generating a first combined signal;
• combining the second product signal with the fourth product signal, thereby generating a second combined signal;
• multiplying the first combined signal by the second combined signal, thereby generating an error signal;
• and
• adjusting, in response to the error signal, a level of the VCO-sine signal and a level of the VCO-cosine signal.

A spread-spectrum-phase-locked-loop apparatus, for use as part of a spread-spectrum receiver on a received-spread-spectrum signal generated from spread-spectrum processing a symbol-sequence signal with a chip-sequence signal, comprising:

• a code generator for generating a replica of the chip-sequence signal;
• a first symbol-matched filter having an in-phase-symbol-impulse response matched to the replica of the chip-sequence signal, for despreading an in-phase component of the received-spread-spectrum signal as a despread-in-phase component of a symbol-sequence signal;
• a second symbol-matched filter having a quadrature-phase-symbol-impulse response matched to the replica of the chip-sequence signal, for despreading a quadrature-phase component of the received-spread-spectrum signal as a despread-quadrature-phase component of a symbol-sequence signal;
• a voltage-controlled oscillator (VCO) for generating a VCO-sine signal and a VCO-cosine signal, with the VCO-cosine signal having a phase 90.degree. from the VCO-sine signal;
• a first product device coupled to said first symbol-matched filter and to said voltage-controlled oscillator, for multiplying the despread-in-phase component of the symbol-sequence signal by the VCO-cosine signal, thereby generating a first product signal;
• a second product device coupled to said first symbol-matched filter and to said voltage-controlled oscillator, for multiplying the despread-in-phase component of the symbol-sequence sequence signal by the VCO-sine signal, thereby generating a second product signal;
• a third product device coupled to said second symbol-matched filter and to said voltage-controlled oscillator for multiplying the despread-quadrature-phase component of the symbol-sequence signal by the VCO-sine signal, thereby generating a third product signal;
• a fourth product device coupled to said second symbol-matched filter and to said voltage-controlled oscillator for multiplying the despread-quadrature-phase component of the symbol-sequence signal by the VCO-cosine signal, thereby generating a fourth product signal;
• a first combiner, coupled to said first product device and to said third product device, for combining the first product signal with the third product signal, thereby generating a first combined signal;
• a second combiner, coupled to said second product device and to said fourth product device, for combining the second product signal with the fourth product signal, thereby generating a second combined signal;
• a fifth product device, coupled to said first combiner and to said second combiner, for multiplying the first combined signal by the second combined signal, thereby generating an error signal;
• and
• wherein said voltage-controlled oscillator, responsive to the error signal, adjusts a level of the VCO-sine signal and a level of the VCO-cosine signal.