Digital-analog shared circuit in dual mode radio equipment
First Claim
1. A digital-analog shared circuit in dual mode radio equipment having a digital mode and an analog mode, said digital-analog shared circuit comprising:
- an analog receiver for obtaining an analog baseband signal by downconverting a received signal by a local oscillation frequency;
a digital receiver for obtaining a digital baseband signal consisting of an in-phase signal and a quadrature signal by quadrature detecting said received signal;
a digital transmitter for generating a digital transmitted signal by quadrature modulating a digital baseband signal;
an analog transmitter for generating an analog transmitted signal by frequency modulating a local oscillation frequency signal by an analog baseband signal; and
a control circuit for switching between the digital mode and the analog mode by controlling said analog receiver and said digital receiver, and by controlling said digital transmitter and said analog transmitter,wherein said digital receiver includes a first frequency synthesizer for generating a first local oscillation frequency for the quadrature detection in response to a first control signal from said control circuit, said first frequency synthesizer generating, in response to a second control signal from said control circuit, a second local oscillation frequency which is supplied to said analog receiver as a local oscillation signal for the downconversion,said digital transmitter including a second frequency synthesizer for generating a third local oscillation frequency for the quadrature modulation in response to a third control signal from said control circuit, said second frequency synthesizer generating, in response to a fourth control signal from said control circuit, a fourth local oscillation frequency for analog modulation, said second frequency synthesizer including a modulator for frequency modulating the analog baseband signal.
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Abstract
A digital-analog shared circuit in dual mode radio equipment, which shares a local oscillator in a digital mode and analog mode. A first frequency synthesizer generates a first and a second local oscillation frequency in a digital and an analog receiving mode, respectively, in response to a control signal from a switching control. In the digital receiving mode, a quadrature demodulater including a first and a second demodulator in a demodulator section is enabled, and carries out quadrature detection of a received signal fed from an RF stage, thereby supplying the detected signal to a baseband signal processor stage. In the analog receiving mode, a buffer to which the second local oscillation frequency is supplied is enabled to deliver the second local oscillation frequency to the analog IF stage. A second frequency synthesizer generates a third local oscillation frequency in a digital transmitting mode and a fourth local oscillation frequency in an analog transmitting mode. In the digital transmitting mode, a quadrature modulator including a first and a second modulator is enabled to carry out quadrature modulation using the third local oscillation frequency. In the analog transmitting mode, the fourth local oscillation frequency undergoes frequency modulation by an analog modulating signal, and the modulated signal is in turn supplied to the RF stage through the second modulator.
108 Citations
7 Claims
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1. A digital-analog shared circuit in dual mode radio equipment having a digital mode and an analog mode, said digital-analog shared circuit comprising:
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an analog receiver for obtaining an analog baseband signal by downconverting a received signal by a local oscillation frequency; a digital receiver for obtaining a digital baseband signal consisting of an in-phase signal and a quadrature signal by quadrature detecting said received signal; a digital transmitter for generating a digital transmitted signal by quadrature modulating a digital baseband signal; an analog transmitter for generating an analog transmitted signal by frequency modulating a local oscillation frequency signal by an analog baseband signal; and a control circuit for switching between the digital mode and the analog mode by controlling said analog receiver and said digital receiver, and by controlling said digital transmitter and said analog transmitter, wherein said digital receiver includes a first frequency synthesizer for generating a first local oscillation frequency for the quadrature detection in response to a first control signal from said control circuit, said first frequency synthesizer generating, in response to a second control signal from said control circuit, a second local oscillation frequency which is supplied to said analog receiver as a local oscillation signal for the downconversion, said digital transmitter including a second frequency synthesizer for generating a third local oscillation frequency for the quadrature modulation in response to a third control signal from said control circuit, said second frequency synthesizer generating, in response to a fourth control signal from said control circuit, a fourth local oscillation frequency for analog modulation, said second frequency synthesizer including a modulator for frequency modulating the analog baseband signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification