Dual-mode radio receiver for receiving narrowband and wideband signals
First Claim
1. A radio receiver for receiving radio signals containing first narrowband signals at a first radio channel frequency and second narrowband signals at a second radio channel frequency, comprising:
- a. a downconverter for downconverting the radio signals to generate downconverted signals;
b. wideband filter means for filtering the downconverted signals with a wide filter bandwidth to generate filtered signals, wherein the filtered signals have a first subband containing the first narrowband signals and a second subband containing the second narrowband signals;
c. a digitizer for digitizing the filtered signals to generate digital signals, wherein the digital signals represent the radio signals in polar form and include phase signals and amplitude signals,d. first frequency-shifting means for shifting the digital signals so as to shift the first narrowband signals by adding a first phase slope to the phase signals to a predetermined center frequency and generate first frequency-shifted signals;
e. second frequency-shifting means for shifting the digital signals so as to shift the second narrowband signals by adding a second phase slope to the phase signals to the predetermined center frequency and generate second frequency-shifted signals,f. narrowband filter means for filtering the frequency-shifted signals with a filter bandwidth adapted to the narrowband signals so as to extract the first and second narrowband signals; and
g. demodulator means for demodulating the extracted first and second narrowband signals and generating demodulated signals.
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Accused Products
Abstract
A radio receiver for a radio operable in a radio communication system utilizing either a wideband standard such as GSM or a narrowband standard such as IS-54. The radio receiver has a wideband mode for demodulating wideband signals and a narrowband mode for demodulating narrowband signals. The radio receiver uses a wideband filter apparatus having a wide filter bandwidth adapted to the wideband signals for filtering both the wideband and narrowband signals. When in the narrowband mode, a digitizer digitizes the filtered signals containing the narrowband signal and produces digital signals having amplitude and phase signals corresponding to the filtered signals. A digital signal processor is used to frequency shift the digital signals so as to shift the narrowband signals to the center frequency of the wideband filter apparatus. The frequency-shifted narrowband signals are then filtered to select the centered narrowband signals and the narrowband signals are then demodulated. The digital signal processor is adapted to frequency-shift a plurality of different narrowband signals at different radio channel frequencies and to demodulated the different narrowband signals to provide for diversity combination.
206 Citations
37 Claims
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1. A radio receiver for receiving radio signals containing first narrowband signals at a first radio channel frequency and second narrowband signals at a second radio channel frequency, comprising:
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a. a downconverter for downconverting the radio signals to generate downconverted signals; b. wideband filter means for filtering the downconverted signals with a wide filter bandwidth to generate filtered signals, wherein the filtered signals have a first subband containing the first narrowband signals and a second subband containing the second narrowband signals; c. a digitizer for digitizing the filtered signals to generate digital signals, wherein the digital signals represent the radio signals in polar form and include phase signals and amplitude signals, d. first frequency-shifting means for shifting the digital signals so as to shift the first narrowband signals by adding a first phase slope to the phase signals to a predetermined center frequency and generate first frequency-shifted signals; e. second frequency-shifting means for shifting the digital signals so as to shift the second narrowband signals by adding a second phase slope to the phase signals to the predetermined center frequency and generate second frequency-shifted signals, f. narrowband filter means for filtering the frequency-shifted signals with a filter bandwidth adapted to the narrowband signals so as to extract the first and second narrowband signals; and g. demodulator means for demodulating the extracted first and second narrowband signals and generating demodulated signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A radio receiver having a wideband mode for receiving radio signals containing wideband signals and a narrowband mode for receiving radio signals containing narrowband signals, comprising:
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a. a downconverter for downconverting the radio signals to generate downconverted signals; b. wideband filter means for filtering the downconverted signals with a wide filter bandwidth adapted to the wideband signals and generating filtered signals containing the wideband signals or narrowband signals; c. a wideband demodulator for receiving the filtered signals containing wideband signals and demodulating the wideband signals contained in the filtered signals; d. a digitizer for digitizing the filtered signals containing the narrowband signals and generating digital signals; e. first frequency-shifting means for shifting the digital signals so as to shift first narrowband signals at a first radio channel frequency to a desired center frequency and generate first frequency-shifted signals; f. narrowband filter means for filtering the first frequency-shifted signals with a filter bandwidth adapted to the first narrowband signals so as to extract the first narrowband signals; and g. a narrowband demodulator for demodulating the extracted first narrowband signals to generate first demodulated signals. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A method for receiving radio signals with a radio receiver where the radio signals contain first narrowband signals at a first radio channel frequency and second narrowband signals at a second radio channel frequency, comprising:
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a. downconverting the radio signals to generate downconverted signals; b. filtering the downconverted signals with a wide filter bandwidth to generate filtered signals, wherein the filtered signals have a first subband containing the first narrowband signals and a second subband containing the second narrowband signals; c. digitizing the filtered signals to generate digital signals, wherein the digital signals represent the radio signals in polar form and include phase signals and amplitude signals; d. frequency shifting the digital signals so as to shift the first narrowband signals by adding a first phase slope to the phase signals to a predetermined center frequency and generate first frequency-shifted signals; e. frequency shifting the digital signals so as to shift the second narrowband signals by adding a second phase slope to the phase signals to the predetermined center frequency and generate second frequency-shifted signals, f. filtering the frequency-shifted signals with a filter bandwidth adapted to the narrowband signals so as to extract the first and second narrowband signals; and g. demodulating the extracted first and second narrowband signals to generate demodulated signals. - View Dependent Claims (25, 26, 27, 28, 29)
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30. A method for receiving radio signals with a radio receiver where the radio signals contain alternatively wideband signals or narrowband signals, comprising:
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a. downconverting the radio signals to generate downconverted signals; b. filtering the downconverted signals with a wide filter bandwidth adapted to the wideband signals to generate filtered signals alternatively containing the wideband signals or narrowband signals; c. demodulating the filtered signals containing wideband signals and demodulating the wideband signals contained in the filtered signals; d. digitizing the filtered signals containing the narrowband signals to generate digital signals; e. frequency shifting the digital signals so as to shift first narrowband signals at a first radio channel frequency to a predetermined center frequency and generate first frequency-shifted signals; f. filtering the first frequency-shifted signals with a filter bandwidth adapted to the first narrowband signals so as to extract the first narrowband signals; and g. demodulating the extracted first narrowband signals to generate first demodulated signals.
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31. A radio communication system for communicating with radios alternatively by wideband signals and narrowband signals, comprising:
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a. a first narrowband transceiver for transmitting first narrowband signals; b. a second narrowband transceiver for transmitting second narrowband signals; c. a wideband transceiver for transmitting wideband signals; and d. a radio including a radio receiver having a wideband mode for receiving radio signals containing wideband signals and a narrowband mode for receiving radio signals containing narrowband signals, the radio receiver including; i) a downconverter for downconverting the radio signals to generate downconverted signals; ii) wideband filter means for filtering the downconverted signals with a wide filter bandwidth adapted to the wideband signals and generating filtered signals containing the wideband signals or narrowband signals, wherein the filtered signals containing the narrowband signals have a first subband containing the first narrowband signals and a second subband containing the second narrowband signals; iii) a wideband demodulator means for receiving the filtered signals containing wideband signals and demodulating the wideband signals contained in the filtered signals; iv) a digitizer for digitizing the filtered signals containing the narrowband signals and generating digital signals; v) first frequency-shifting means for shifting the digital signals so as to shift the first narrowband signals to a predetermined center frequency and generate first frequency-shifted signals; vi) second frequency-shifting means for shifting the digital signals so as to shift the second narrowband signals to the predetermined center frequency and generate second frequency-shifted signals, vii) narrowband filter means for filtering the frequency-shifted signals with a filter bandwidth adapted to the narrowband signals so as to extract the first and second narrowband signals; and viii) a narrowband demodulator means for demodulating the extracted first and second narrowband signals and generating demodulated signals. - View Dependent Claims (32, 33, 34, 35, 36, 37)
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Specification