Dual-mode radiotelephone apparatus for digital or analog modulation
AssigneeEricsson Inc.
InventorPaul W. Dent
Life of this patent
Estimating the term…
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.
Claims31
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.
A radio transmitter/receiver for selectively transmitting a bandwidth-compressed digital speech signal or an amplitude-compressed analog speech signal comprising:
- 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.
An apparatus for alternatively modulating a carrier signal with an analog signal or a digital signal, comprising:
- 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.
A radio transmitter/receiver for selectively transmitting digitally modulated signals in a digital mode or analog modulated signals in an analog mode comprising:
- 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.
A method for selectively transmitting digitally modulated signals in a digital mode or analog modulated signals in an analog mode comprising the steps of:
- 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.
Dependencies are inferred from the claim text.