Combined digital filter and correlator
First Claim
1. A radio frequency (RF) receiver comprising:
- an RF mixer adapted to;
receive an RF input signal based on a first reference code, such that the first RF input signal comprises at least one interference signal having interfering frequency content and the at least one interference signal comprises at least one non-correlating interference signal having non-correlating interfering frequency content; and
down-convert the RF input signal with a local oscillator signal to provide a down-converted RF input signal;
an analog-to-digital converter (ADC) adapted to sample the down-converted RF input signal using a sampling clock to provide a sampled input signal;
correlation and filtering circuitry adapted to correlate and filter the sampled input signal by;
mixing the sampled input signal with a modified first reference code to provide a discrete correlation having at least two correlation elements, such that the modified first reference code is based on the first reference code and filtering characteristics, and is further based on the non-correlating interfering frequency content, such that the filtering characteristics reduce effects of the interfering frequency content on a filtered correlation signal; and
summing the at least two correlation elements to provide the filtered correlation signal.
3 Assignments
0 Petitions
Accused Products
Abstract
The present invention is a combined digital filter and correlator, which is used in a radio frequency (RF) receiver, and takes advantage of common structures used in both digital filters and correlators. Specifically, a digital filter may mix (multiply) digital filter coefficients with samples of a down-converted RF signal, and then sum the resulting products to provide filtered samples of the down-converted RF signal. Similarly, a correlator may mix (multiply) a reference code with the samples of the down-converted RF signal, and then sum the resulting products to provide a correlation of the down-converted RF signal. The present invention combines the digital filter coefficients and the reference code into a modified reference code, which is then mixed with the samples of the down-converted RF signal and summed to provide a filtered correlation of the down-converted RF signal.
30 Citations
27 Claims
-
1. A radio frequency (RF) receiver comprising:
-
an RF mixer adapted to; receive an RF input signal based on a first reference code, such that the first RF input signal comprises at least one interference signal having interfering frequency content and the at least one interference signal comprises at least one non-correlating interference signal having non-correlating interfering frequency content; and down-convert the RF input signal with a local oscillator signal to provide a down-converted RF input signal; an analog-to-digital converter (ADC) adapted to sample the down-converted RF input signal using a sampling clock to provide a sampled input signal; correlation and filtering circuitry adapted to correlate and filter the sampled input signal by; mixing the sampled input signal with a modified first reference code to provide a discrete correlation having at least two correlation elements, such that the modified first reference code is based on the first reference code and filtering characteristics, and is further based on the non-correlating interfering frequency content, such that the filtering characteristics reduce effects of the interfering frequency content on a filtered correlation signal; and summing the at least two correlation elements to provide the filtered correlation signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
-
-
27. A method of operation of a radio frequency (RF) receiver comprising:
-
receiving an RF input signal based on a first reference code, such that the first RF input signal comprises at least one interference signal having interfering frequency content and the at least one interference signal comprises at least one non-correlating interference signal having non-correlating interfering frequency content; down-converting the RF input signal with a local oscillator signal to provide a down-converted RF input signal; sampling the down-converted RF input signal using an analog-to-digital converter (ADC) and a sampling clock to provide a sampled input signal; correlating and filtering the sampled input signal by; mixing the sampled input signal with a modified first reference code to provide a discrete correlation having at least two correlation elements, such that the modified first reference code is based on the first reference code and filtering characteristics, and is further based on the non-correlating interfering frequency content, such that the filtering characteristics reduce effects of the interfering frequency content on a filtered correlation signal; and summing the at least two correlation elements to provide the filtered correlation signal.
-
Specification