Quadrature local oscillator network

A quadrature local oscillator network comprising:

• a first quadrature circuit for dividing a first input signal into a first in-phase signal and a first quadrature signal 90.degree. out of phase;
• a second quadrature circuit for dividing a second input signal into a second in-phase signal and a second quadrature signal 90.degree. out of phase;
• a first mixer for mixing said first in-phase signal and said second in-phase signal;
• a second mixer for mixing said first quadrature signal and said second quadrature signal;
• a third mixer for mixing said first quadrature signal and said second in-phase signal;
• a fourth mixer for mixing said first in-phase signal and said second quadrature signal;
• a first combiner for combining the outputs of said first and second mixers into a first local oscillator output signal;
• a second combiner for combining the outputs of said third and fourth mixers into a second local oscillator output signal;
• a first amplitude limiting amplifier connected to the first combiner;
• and
• a second amplitude limiting amplifier connected to the second combiner, wherein said first and second local oscillator output signals have substantially equal amplitudes and a substantially balanced quadrature phase relationship.

A method of quadrature modulating and demodulating signals in the transceiver of a portable radiotelephone using a quadrature local oscillator network comprising a first quadrature circuit for dividing a first input signal into a first in-phase signal and a first quadrature signal 90.degree. out of phase;

• a second quadrature circuit for dividing a second input signal into a second in-phase signal and a second quadrature signal 90.degree. out of phase;
• a first mixer for mixing said first in-phase signal and said second in-phase signal;
• a second mixer for mixing said first quadrature signal and said second quadrature signal;
• a third mixer for mixing said first quadrature signal and said second in-phase signal;
• a fourth mixer for mixing said first in-phase signal and said second quadrature signal;
• a first combiner for combining the outputs of said first and second mixers into a first local oscillator output signal;
• and a second combiner for combining the outputs of said third and fourth mixers into a second local oscillator output signal

A method of quadrature modulating and demodulating signals in the transceiver of a base station using a quadrature local oscillator network comprising:

• a first quadrature circuit for dividing a first input signal into a first in-phase signal and a first quadrature signal 90.degree. out of phase;
• a second quadrature circuit for dividing a second input signal into a second in-phase signal and a second quadrature signal 90.degree. out of phase;
• a first mixer for mixing said first in-phase signal and said second in-phase signal;
• a second mixer for mixing said first quadrature signal and said second quadrature signal;
• a third mixer for mixing said first quadrature signal and said second in-phase signal;
• a fourth mixer for mixing said first in-phase signal and said second quadrature signal;
• a first combiner for combining the outputs of said first and second mixers into a first local oscillator output signal;
• and a second combiner for combining the outputs of said third and fourth mixers into a second local oscillator output signal.

A quadrature modulator comprising:

• a first quadrature circuit for dividing a first input signal into a first in-phase signal and a first quadrature signal 90.degree. out of phase;
• a second quadrature circuit for dividing a second input signal into a second in-phase signal and a second quadrature signal 90.degree. out of phase;
• a first mixer for mixing said first in-phase signal and said second in-phase signal;
• a second mixer for mixing said first quadrature signal and said second quadrature signal;
• a third mixer for mixing said first quadrature signal and said second in-phase signal;
• a fourth mixer for mixing said first in-phase signal and said second quadrature signal;
• a first combiner for combining the outputs of said first and second mixers into a first local oscillator output signal;
• a second combiner for combining the outputs of said third and fourth mixers into a second local oscillator output signal;
• said first and second local oscillator output signals have equal amplitudes and a balanced quadrature phase relationship;
• a fifth mixer for mixing a first data signal and said first local oscillator output signal to produce a first modulated signal;
• a sixth mixer for mixing a second data signal and said second local oscillator output signal to produce a second modulated signal;
• and
• a third combiner for combining said first and second modulated signals to produce an output quadrature modulated signal.

A quadrature modulator, comprising:

• first and second single side band (SSB) networks receiving first and second input signals, wherein the first SSB network mixes in-phase components of the first and second input signals and quadrature components of the first and second input signals and combines these first mixed signals to generate an in-phase signal, and the second SSB network selectively mixes in-phase and quadrature components of the input signals and combines the selectively mixed signals to generate a quadrature signal such that the in-phase and quadrature signals are equal in amplitude and out of phase by 90.degree.;
• a first mixer for mixing the in-phase signal with a first data signal to produce a first modulated signal;
• a second mixer for mixing the quadrature signal with a second data signal to produce a second modulated signal;
• and
• a combiner for combining the first and second modulated signals to produce a quadrature modulated output signal.