Method and apparatus for sampling RF signals
The invention provides a method and apparatus used in a receiver for sampling RF signals, particularly to provide a method and apparatus for greatly decrease the sampling rate performed in RF band. The invention provides an apparatus for sampling a RF signal including a plurality of interference frequency components and a useful frequency component, comprising: a filtering unit for filtering out at least one preset interference frequency component from the RF signal to generate a notch-filtered RF signal; a sampling unit for sampling the notch-filtered RF signal at a preset sampling rate to generate a discrete analog signal. The sampling unit can be implemented by a plurality of notch filters. RF sampling can be simply and conveniently implemented by using the method and apparatus according the invention, and the sampling rate can be decreased to about 1/N of the carrier frequency of the useful frequency component, which is much lower than the sampling rate in existing RF sampling scheme. The method and apparatus according the invention can greatly decrease power dissipation when sampling.
1. A device for sampling a RF signal comprising a plurality of interference Frequency components and a useful frequency component, comprising:
a filtering unit for filtering out at least one predefined interference frequency component from the RF signal to generate a filtered RF signal;
sampling unit for sampling the filtered RF signal at a predefined sampling rate to generate a time-discrete analog signal, wherein the filtered RF signal is a notch-filtered RF signal and the difference value of a center frequency of the predefined interference frequency component and a predefined intermediate frequency is a multiple of the sampling rate.
2. The device of claim 1 , wherein the intermediate frequency is one of a zero frequency and a predefined low IF, wherein the predefined low IF being much lower than the center frequency of the useful frequency component.
3. The device of claim 1 , wherein the filtering unit comprises at least one notch filter for filtering out the one predefined interference frequency component.
4. The device of claim 1 , further comprising:
a bandpass filter for bandpass filtering the RF signal to generate a bandpassfiltered RF signal comprising the useful frequency component and the at least one predefined interference frequency components; and
a low noise amplifier for amplifying the bandpass-filtered RF signal to generate an amplified bandpass-filtered RF signal and transferring the amplified bandpassfiltered RF to the filtering unit.
5. The device of claim 1 , further comprising:
a discrete filter for suppressing out-of-band interferences of the discrete analog signal to generate a filtered discrete analog signal;
an analog-to-digital converter for transforming the filtered discrete analog signal into a digital signal.
6. A receiver for use in a wireless communication network, comprising:
a RF sampling unit for sampling a RF signal comprising a plurality of interference frequency components and a useful frequency component, wherein the RF sampling unit further comprises:
a filtering unit for filtering out at least one predefined interference frequency component from the RF signal to generate a filtered RF signal;
a sampling unit for sampling the filtered RF signal at a predefined sampling rate to generate a time discrete analog signal, wherein the filtered RF signal is a notch-filtered RF signal and the difference value of a center frequency of the predefined interference frequency component and a predefined intermediate frequency of a multiple of the sampling rate;
a discrete filter for suppressing out-of-band interferences of the discrete analog signal to generate a filtered time discrete analog signal;
an analog-to-digital converter for transforming the filtered discrete analog signal into a digital signal;
a digital signal processing unit for processing the digital signal.
7. The receiver of claim 6 , wherein the intermediate frequency is one of a zero frequency and a predefined low IF, wherein the predefined low IF being much lower than the center frequency of the useful frequency component.
8. A method for sampling a RF signal comprising a plurality of interference frequency components and a useful frequency component, the method comprising:
a) filtering out at least one predefined interference frequency component from the RF signal to generate a filtered RF signal;
b) sampling the filtered RF signal at a predefined sampling rate to generate a time-discrete analog signal wherein the filtered RF signal is a notch-filtered RF signal and the difference value of a center frequency of the predefined interference frequency component and a predefined intermediate frequency is a multiple of the sampling rate.
9. The method of claim 8 , wherein the intermediate frequency is one of a zero frequency and a predefined low IF, wherein the predefined low IF being much lower than the center frequency of the useful frequency component.
10. The method of claim 8 , wherein in the step a) using at least one notch filter to filter out the one predefined interference frequency component.
11. The method of claim 8 , further comprising:
c) performing bandpass filtering on the RF signal to suppress out-of-band interferences of the useful frequency component to generate a bandpass-filtered RF signal;
d) amplifying the bandpass-filtered RF signal to be used for filtering process of the step a).
12. The method of clam 8 , further comprising:
c) filtering the time-discrete analog signal to generate a filtered time discrete analog signal;
d) performing analog and digital converting on the filtered discrete analog signal to generate a digital signal.