| 摘要 |
The invention relates to the field of multi-standard receiver that can be applied to wireless multi-mode transceivers in a cellular communication system. It particularly refers to an analog front end of a digital dual-mode intermediate frequency (IF) sampling receiver architecture with two reception chains (401, 403, 404, 405 and 401, 403, 406, 407) and a signal processing chain (410, 411, 412, 413) for selectively receiving, processing and down-converting modulated RF signal spectra of a first (GSM/ GPRS (DCS) 1,800 MHz Rx, GSM/GPRS (PCS) 1,900 MHz Rx, and UMTS TDD Rx) or a second frequency band (GSM/GPRS 850 MHz Rx, GSM/GPRS 900 MHz Rx) from the passband to a common IF band, which can advantageously be applied to a wireless communication device in a cellular telecommunication system based on UMTS or GSM/GPRS technology. <??>The IF sampling receiver architecture thereby comprises means (408, 408a) for up-converting the modulated RF signal spectrum of a second frequency band (GSM/GPRS 850 MHz Rx, GSM/GPRS 900 MHz Rx) to a first frequency band (GSM/GPRS (DCS) 1,800 MHz Rx, GSM/GPRS (PCS) 1,900 MHz Rx, and UMTS TDD Rx) and switching means (409) for selectively switching either the modulated RF signal spectrum of said first or said second frequency band (GSM/GPRS 850 MHz Rx, GSM/GPRS 900 MHz Rx) to a common signal processing chain for further processing. According to a further aspect of the invention, a sigma-delta analog-to-digital converter 414 (SDADC) is connected to the output port of the signal processing chain (410, 411, 412, 413), which provides a time- and amplitude-quantized time-domain representation of the down-converted RF signal spectrum of either said first or second frequency band, which allows to obtain high linearity and signal-to-noise ratio (SNR) by means of oversampling and spectral shaping of the quantization noise. <IMAGE>
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