| 摘要 |
#CMT# #/CMT# The method involves performing analog filtering of an incident analog signal using analog low pass filters (FPBAI, FPBAQ) for filtering frequency components located outside a desired frequency range e.g. useful signal bandwidth. The filtered analog signal is converted into a digital signal using analog-digital conversion stages (CANI, CANQ). The digital signal is reshaped into a shape identical to the shape of the incident analog signal. The digital filtering of the reshaped digital signal is performed for filtering the frequency components outside the desired frequency range. #CMT# : #/CMT# An independent claim is also included for a device for filtering and converting an incident analog signal into a digital signal. #CMT#USE : #/CMT# Method for filtering and converting an incident analog signal into a digital signal in a filtering and converting device of a radiofrequency signal receiver (all claimed) that is utilized for receiving radiofrequency signal e.g. digital terrestrial TV signal or signal transmitted into a frequency-division multiplexing transmission system. #CMT#ADVANTAGE : #/CMT# The analog filtering of the incident analog signal is performed so as to limit dynamics of an analog to digital converter and to adapt sampling frequency of the converter to the useful signal bandwidth, thus improving analog to digital signal conversion with respect to a useful signal to be converted, while avoiding loss of information or degradation of the signal. The method permits filtering of the useful signal using a digital filter without the need for high dynamic analog-digital converter. The method efficiently prevents un-useful frequency components, and conserves sufficient integrity of the useful bandwidth of the signal. #CMT#DESCRIPTION OF DRAWINGS : #/CMT# The drawing shows a block diagram of an internal structure of a filtering and analog-digital conversion device. CANI, CANQ : Analog-digital conversion stages FPBAI, FPBAQ : Analog low pass filters LNA : Low noise amplifier MXI, MXQ : Mixers REC : Receiver VCO : Voltage controlled oscillator. |
