IPC분류정보
국가/구분 |
United States(US) Patent
등록
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국제특허분류(IPC7판) |
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출원번호 |
UP-0944552
(2004-09-17)
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등록번호 |
US-7515652
(2009-07-01)
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발명자
/ 주소 |
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출원인 / 주소 |
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대리인 / 주소 |
Garlick, Harrison & Markison
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인용정보 |
피인용 횟수 :
10 인용 특허 :
2 |
초록
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A digital modulator in a radio transmitter includes circuitry for switching between Gaussian Minimum Shift Keying (GMSK) and Phase-Shift Keying (PSK) while maintaining spectral mask requirements. The digital modulator of the present invention includes both GMSK and PSK symbol mappers that produce PS
A digital modulator in a radio transmitter includes circuitry for switching between Gaussian Minimum Shift Keying (GMSK) and Phase-Shift Keying (PSK) while maintaining spectral mask requirements. The digital modulator of the present invention includes both GMSK and PSK symbol mappers that produce PSK in-phase and quadrature symbols and GMSK symbols, respectively, to a pulse shaping block. Based on opposite phases of a modulation control signal, the symbol mappers produce either modulated data or a steam of logic zeros to the pulse shaping block. The pulse shaping block filters the received data and multiplexes the data so that each modulated data stream receives non-zero data during a guard time to avoid abrupt changes in the modulated signal that would violate the spectral mask requirements.
대표청구항
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What is claimed is: 1. A polar radio frequency (RF) transmitter within a radio transceiver for producing Phase Shift Keying (PSK) and Gaussian Minimum Shift Keying (GMSK) modulated communication signals, comprising: a baseband processor for producing transmission (TX) data and a TX control signal;
What is claimed is: 1. A polar radio frequency (RF) transmitter within a radio transceiver for producing Phase Shift Keying (PSK) and Gaussian Minimum Shift Keying (GMSK) modulated communication signals, comprising: a baseband processor for producing transmission (TX) data and a TX control signal; a digital modulator that receives the TX data, that digitally modulates the TX data to produce one of a PSK and GMSK symbol based upon the TX control signal, wherein the digital modulator further includes: a modulation switching control block that receives the TX control signal, producing a modulation control signal to select one of a PSK modulation and GMSK modulation mode; a PSK symbol mapper operably coupled to receive the TX data that produces in-phase and quadrature phase PSK symbols based on the TX data and further based on a first value of the modulation control signal and that produces logic zero digital signals based on a second value of the modulation control signal; a GMSK symbol mapper operably coupled to receive the TX data that produces binary GMSK symbols based on the TX data and further based on the second value of the modulation control signal and that produces logic zero signals based on the first value of the modulation control signal; a pulse shaping block for filtering the PSK and GMSK symbols, wherein the pulse shaping block produces filtered PSK symbols for the first value of the modulation control signal and produces filtered GMSK symbols for the second value of the modulation control signal; envelope path adjustment circuitry operably coupled to receive the filtered PSK symbols that produces an envelope signal and a PSK phase signal; and phase path adjustment circuitry operably coupled to receive the filtered GMSK symbols and the PSK phase signal produced by the envelope path adjustment circuitry, wherein the phase path adjustment circuitry produces a phase signal based on the filtered GMSK symbols and the PSK phase signal; first and second Digital-to-Analog converters (DACs) for converting the envelope signal and the phase signal, respectively, from digital signals to analog signals to produce analog envelope signal and analog phase signal; first and second low pass filters for filtering the analog envelope signal and the analog phase signal, respectively; translational loop operably coupled to receive the analog phase signal to up-convert the analog phase signal from an IF frequency to an RF frequency; and a power amplifier for producing a modulated RF signal based on the RF frequency analog phase signal and the analog envelope signal. 2. The polar RF transmitter of claim 1 wherein the pulse shaping block comprises one of a Finite Impulse Response (FIR) filter and an Infinite Impulse Response (IIR) filter. 3. The polar RF transmitter of claim 1 wherein a gain select block increases a gain magnitude of the GMSK symbol based on a baseband gain select signal. 4. The polar RF transmitter of claim 1 further including an envelope and phase extraction block that comprises a COordinate Rotation DIgital Computer (CORDIC). 5. The polar RF transmitter of claim 1 wherein the PSK symbol mapper further includes: a phasor look-up table for mapping the TX data to a plurality of magnitude signals; an integrator for producing a polar signal having a constant angular frequency; and a multiplier for multiplying the plurality of magnitude signals by the constant angular frequency to produce in-phase and quadrature phase signals. 6. A polar radio frequency (RF) transmitter within a radio transceiver for producing Phase Shift Keying (PSK) and Gaussian Minimum Shift Keying (GMSK) modulated communication signals, comprising: a baseband processor for producing transmission (TX) data and a TX control signal; a digital modulator that receives the TX data, that digitally modulates the TX data to produce one of a PSK and GMSK modulated digital signal based upon the TX control signal; envelope path adjustment circuitry operably coupled to receive a PSK modulated digital signal that produces an envelope signal and a PSK phase signal, the envelope path adjustment circuitry comprising: envelope and phase extraction block that produces a phase signal and an envelope signal based on the PSK modulated digital signal; envelope magnitude and group delay equalizer block that pre-distorts the envelope signal to substantially compensate for expected distortion in an analog portion of an envelope path; envelope and phase mismatch cancellation block for substantially canceling a timing mismatch between the envelope and a phase path; and envelope signal interpolation block that increases a sampling rate of the PSK modulated digital signal; phase path adjustment circuitry operably coupled to receive the GMSK modulated digital signal and the PSK phase signal produced by the envelope path adjustment circuitry, wherein the phase path adjustment circuitry produces an outgoing phase signal based on the GMSK modulated digital signal and the PSK phase signal; first and second Digital-to-Analog converters (DACs) for converting an outgoing envelope signal and the outgoing phase signal, respectively, from digital signals to analog signals to produce an analog envelope signal and an analog phase signal; first and second low pass filters for filtering the analog envelope signal and the analog phase signal, respectively; translational loop operably coupled to receive the analog phase signal to up-convert the analog phase signal from an IF frequency to an RF frequency; and a power amplifier for producing a modulated RF signal based on the RF frequency analog phase signal and the analog envelope signal. 7. The polar RF transmitter of claim 6 wherein the envelope and phase mismatch cancellation block includes a delay adjustment block that inserts at least one interpolated data bit in the PSK modulated digital signal to increase signal propagation in the envelope signal path. 8. The polar RF transmitter of claim 6 wherein the digital modulator includes: a modulation switching control block that receives the TX control signal, producing a modulation control signal to select one of a PSK modulation and GMSK modulation mode; a PSK symbol mapper operably coupled to receive the TX data and to produce in-phase and quadrature PSK modulated digital signals based on the TX data and a first value of the modulation control signal and to produce logic zeros based on a second value of the modulation control signal; a GMSK symbol mapper operably coupled to receive the TX data and to produce binary GMSK modulated digital signals based on the TX data and the second value of the modulation control signal and to produce logic zeros based on the first value of the modulation control signal; and a pulse shaping block for filtering the PSK and GMSK modulated digital signals, wherein the pulse shaping block produces filtered PSK modulated digital signals during the first value of the modulation control signal and produces filtered GMSK modulated digital signals during the second value of the modulation control signal. 9. The polar RF transmitter of claim 8 wherein the PSK and GMSK modulated digital signals are multiplied by filter coefficients corresponding to one of a Finite Impulse Response (FIR) filter and an Infinite Impulse Response (IIR) filter. 10. A polar radio frequency (RF) transmitter within a radio transceiver for producing Phase Shift Keying (PSK) and Gaussian Minimum Shift Keying (GMSK) modulated communication signals, comprising: a baseband processor for producing transmission (TX) data and a TX control signal; a digital modulator that receives the TX data, that digitally modulates the TX data to produce one of a PSK and GMSK modulated digital signal based upon the TX control a phase path; envelope path adjustment circuitry operably coupled to receive the PSK modulated digital signal that produces a PSK phase signal and an outgoing envelope signal; phase path adjustment circuitry operably coupled to receive the GMSK modulated digital signal and the PSK phase signal produced by the envelope path adjustment circuitry, wherein the phase path adjustment circuitry produces an outgoing phase signal, the phase path adjustment circuitry comprising: a GMSK modulation index adjust block that adjusts the modulation index based on an index adjust signal; a phase accumulator coupled to receive GMSK phase information, the phase accumulator producing an accumulated phase signal; phase magnitude and group delay equalizer block for pre-distorting the accumulated phase signal to substantially compensate for expected distortion in an analog portion of an envelope path; Direct Digital Frequency Synthesizer (DDFS) block for modulating the pre-distorted phase signal; and phase signal interpolation block for increasing a signaling rate of the outgoing phase signal; first and second Digital-to-Analog converters (DACs) for converting the outgoing envelope signal and the outgoing phase signal, respectively, from digital signals to analog signals to produce an analog envelope signal and an analog phase signal; first and second low pass filters for filtering the analog envelope signal and the analog phase signal, respectively; translational loop operably coupled to receive the analog phase signal to up-convert the analog phase signal from an IF frequency to an RF frequency analog phase signal; and a power amplifier for producing a modulated RF signal based on the RF frequency analog phase signal and the analog envelope signal. 11. The polar RF transmitter of claim 10 wherein the phase path adjustment circuitry further includes a summing junction that sums the PSK phase signal with the accumulated phase signal to provide a smooth transition in the outgoing phase signal during a transition from PSK modulation to GMSK modulation. 12. The polar RF transmitter of claim 10 wherein the digital modulator includes: a modulation switching control block that receives the TX control signal, producing a modulation control signal to select one of a PSK modulation and GMSK modulation mode; a PSK symbol mapper operably coupled to receive the TX data and to produce in-phase and quadrature PSK modulated digital signals based on the TX data and a first value of the modulation control signal and to produce logic zeros based on a second value of the modulation control signal; a GMSK symbol mapper operably coupled to receive the TX data and to produce binary GMSK modulated digital signals based on the TX data and the second value of the modulation control signal and to produce logic zeros based on the first value of the modulation control signal; and a pulse shaping block for filtering the PSK and GMSK modulated digital signals, wherein the pulse shaping block produces filtered PSK modulated digital signals during the first value of the modulation control signal and produces filtered GMSK modulated digital signals during the second value of the modulation control signal. 13. The polar RF transmitter of claim 12 wherein the phase path adjustment circuitry receives an IF adjust signal to adjust a frequency of an IF signal. 14. The polar RF transmitter of claim 12 wherein the PSK and GMSK modulated digital signals are multiplied by filter coefficients corresponding to one of a Finite Impulse Response (FIR) filter and an Infinite Impulse Response (IIR) filter. 15. The polar RF transmitter of claim 12 wherein the PSK symbol mapper includes: a phasor look-up table for mapping the TX data bits to a plurality of magnitude signals; an integrator for producing a polar signal having a constant angular frequency; and a multiplier for multiplying the plurality of magnitude signals by the constant angular frequency to produce in-phase and quadrature phase signals. 16. A method in a polar RF transmitter of a radio transceiver for producing Phase Shift Keying (PSK) and Gaussian Minimum Shift Keying (GMSK) modulated communication signals, the method comprising: producing, in a baseband processor of the radio transceiver, a plurality of transmission (TX) data bits for transmission from the polar RF transmitter of the radio transceiver; modulating the TX data bits to generate one of a plurality of PSK signals or a plurality of GMSK signals based on a logical value of a modulation control signal; when the TX data is modulated to generate the plurality of PSK signals, producing phase signals and envelope signals; pre-distorting the phase signals to substantially compensate for expected distortion in an analog portion of a phase path; when the TX data is modulated to generate the plurality of GMSK signals, increasing a sampling rate of the GMSK signals; filtering at least one of the plurality of PSK signals and the plurality of GMSK signals to produce at least one of filtered PSK and GMSK signals based on the modulation control signal; when the TX data is modulated to generate the plurality of GMSK signals, receiving the filtered GMSK signals and receiving, from envelope path adjustment circuitry, PSK phase signals and producing an outgoing signal based on the filtered GMSK signals and the PSK phase signals by adjusting a phase of the filtered GMSK signals based on a PSK phase value of the PSK phase signals; and upconverting the outgoing signal to radio frequency and power amplifying the upconverted radio frequency signal for transmission. 17. The method of claim 16 further comprising: producing in-phase and quadrature PSK signals based on a first value of the modulation control signal and producing logic zeros based on a second value of the modulation control signal. 18. The method of claim 16 further comprising: producing binary GMSK signals based on the second value of the modulation control signal and producing logic zeros based on the first value of the modulation control signal. 19. The method of claim 16 wherein the filtering comprises multiplying the PSK and GMSK signals by one of a plurality of Finite Impulse Response (FIR) filter coefficients or a plurality of Infinite Impulse Response (IIR) filter coefficients. 20. The method of claim 16 wherein the modulating the transmission data bits to PSK signals further includes: mapping the transmission data bits to a plurality of magnitude signals based on a value in a phasor look-up table; and multiplying the plurality of magnitude signals by a polar frequency to produce in-phase and quadrature phase signals.
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