Dual-mode radiotelephone apparatus for digital or analog modulation
First Claim
Patent Images
1. A radio transmitter/receiver for selectively transmitting digitally modulated signals in a digital mode or analog modulated signals in an analog mode comprising:
- digital signal processing means having an input for receiving an information signal, a first output for supplying an In-phase modulating signal I and a second output for supplying a Quadrature modulating signal Q;
quadrature modulation means coupled to the first and second outputs for digitally modulating a carrier frequency in the digital mode to produce a digitally modulated signal; and
analog modulation means coupled to the first and second outputs for generating an analog modulation of a carrier frequency in the analog mode to produce an analog modulated signal, wherein said In-phase modulating signal I and said Quadrature modulating signal Q bypass said quadrature modulation means in order to produce said analog modulated signal.
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Abstract
A dual-mode radiotelephone capable of operation in analog or digital modes. According to exemplary embodiments, a digital signal processor receives a speech signal to be transmitted in the digital or analog mode and generates In-phase (I) and Quadrature (Q) modulating signals. The I and Q signals are supplied to a quadrature modulator for generating a digitally modulated signal and are supplied to an analog modulator for generating an analog modulated signal.
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Citations
31 Claims
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1. A radio transmitter/receiver for selectively transmitting digitally modulated signals in a digital mode or analog modulated signals in an analog mode comprising:
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digital signal processing means having an input for receiving an information signal, a first output for supplying an In-phase modulating signal I and a second output for supplying a Quadrature modulating signal Q;
quadrature modulation means coupled to the first and second outputs for digitally modulating a carrier frequency in the digital mode to produce a digitally modulated signal; and
analog modulation means coupled to the first and second outputs for generating an analog modulation of a carrier frequency in the analog mode to produce an analog modulated signal, wherein said In-phase modulating signal I and said Quadrature modulating signal Q bypass said quadrature modulation means in order to produce said analog modulated signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A radio transmitter/receiver for selectively transmitting a bandwidth-compressed digital speech signal or an amplitude-compressed analog speech signal comprising:
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analog-to-digital conversion means having an input for receiving an analog speech signal and an output for producing a sample stream of numerical samples representative of the analog speech signal;
digital signal processing means having an input for receiving the sample stream and one or more outputs for supplying an In-phase modulating signal I and a Quadrature modulating signal Q, the digital signal processing means converting the sample stream into a bandwidth-compressed and coded digital speech signal and an I and a Q sample stream representative of a digital vector modulation of the bandwidth-compressed digital speech signal or a numerical stream on at least one of the outputs representative of an amplitude-companded version of the analog speech signal;
digital-to-analog conversion means for converting the I and Q sample streams to associated I and Q analog modulating waveforms;
quadrature modulator means coupled to the digital-to-analog conversion means for vector modulating a carrier frequency with the I and Q analog modulating waveforms for transmitting the bandwidth-compressed digital speech signal; and
analog modulation means coupled to the digital-to-analog conversion means for producing an analog modulation of a carrier frequency using at least one of the I or Q analog modulating waveforms for transmitting the amplitude-compressed analog speech signal. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. An apparatus for alternatively modulating a carrier signal with an analog signal or a digital signal, comprising:
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digital signal processing means for generating a first pair of delta-modulation bitstreams representative of either a balanced In-phase component of a digitally modulated signal or an unbalanced high-frequency component of an analog frequency modulated signal plus an In-phase balanced low-frequency component, and a second pair of delta-modulation bitstreams representative of either a balanced Quadrature component of a digitally modulated signal or a balanced Quadrature low-frequency component of an analog modulation waveform;
Quadrature modulator means, responsive to the balanced In-phase and Quadrature signals, for Quadrature-modulating the carrier signal; and
frequency modulation means responsive to the unbalanced high-frequency component for frequency modulating the carrier signal, wherein the carrier signal is either quadrature modulated with a digital modulation signal or frequency or phase modulated with both a low-frequency and a high-frequency component of an analog modulation signal. - View Dependent Claims (26)
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27. A radio transmitter/receiver for selectively transmitting digitally modulated signals in a digital mode or analog modulated signals in an analog mode comprising:
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a digital signal processor having an input for receiving an information signal, a first output for supplying an In-phase modulating signal I and a second output for supplying a Quadrature modulating signal Q;
a quadrature modulator coupled to the first and second outputs for digitally modulating a carrier frequency in the digital mode to produce a digitally modulated signal;
a selecting unit coupled to the first and second outputs for selecting said In-phase modulating signal I and said Quadrature modulating signal Q and generating a modulating waveform, or a combining unit coupled to the first and second outputs for combining said In-phase modulating signal I and said Quadrature modulating signal Q and generating a modulating waveform; and
an analog modulator for receiving said modulating waveform and producing an analog modulated signal. - View Dependent Claims (28, 29)
wherein one of said In-phase modulating signal I or said Quadrature modulating signal Q is used to frequency modulate the voltage controlled oscillator while the other signal is injected into a synthesizer loop controlling the voltage controlled oscillator.
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30. A method for selectively transmitting digitally modulated signals in a digital mode or analog modulated signals in an analog mode comprising the steps of:
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phase receiving an information signal in a digital signal processor and generating an In-phase modulating signal I and a Quadrature modulating signal Q;
determining whether a digital mode or an analog mode has been selected;
digitally modulating, in a quadrature modulator, a carrier frequency to produce a digitally modulated signal if said digital mode has been selected;
selecting, if said analog mode has been selected, an In-phase modulating signal I or a Quadrature modulating signal Q, or combining an In-phase modulating signal I and a Quadrature modulating signal Q, to produce a modulating waveform; and
generating, in an analog modulator, an analog modulation of a carrier frequency to produce an analog modulated signal using said modulating waveform if said analog mode has been selected. - View Dependent Claims (31)
upconverting said digitally modulated signal, if said digital mode has been selected, from a first frequency to a second frequency; and
upconverting said analog modulated signal, if said analog mode has been selected, from a third frequency to a fourth frequency.
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Specification