Patent ID: 9571036
Date: 2017-02-14
CPC Classifications: H03D,H04B

Claim:
1. A heterodyne receiver structure comprising: a frequency conversion block arranged, by aid of a local oscillator, to convert an incoming analog radio frequency (RF) signal to an analog intermediate frequency (IF) signal; a filter block configured to filter said analog IF signal; an analog-to-digital (AD) converter block arranged, by aid of a sampling clock, to convert said filtered analog IF signal to a digital signal; and a digital signal processing block configured to filter, and to decimate the rate of, the digital signal; wherein the AD converter block is configured to convert the filtered analog IF signal to the digital signal by using a sampling frequency that is at least N times a maximum bandwidth of the filtered analog IF signal, where the frequency spectrum from zero to the sampling frequency is divided into N frequency zones of equal width, with N being an even positive number higher than two; wherein the frequency conversion block is configured to convert the incoming analog RF signal to the analog IF signal such that the analog IF signal is located in any of the N/2-1 frequency zones having lowest frequency; and wherein the filter block is configured to low pass the analog IF signal such that any disturbing signal that is located in one of the N frequency zones and which would have a mirror image after the AD conversion in the frequency zone in which the analog IF signal is located is filtered away.