noise at the image frequency
时间：04-12
整理：3721RD
点击：
Hi all,
let's say I have an heterodyne front-end. The first mixer will bring both the signal and noise at image freq on the IF freq. This will lead to a ~3dB NF degradation and thus an image rejection filter is required (for other reasons also...). Next comes an IQ demodulator which rejects the image frequency. What about noise? Does the IQ demodulator reject noise at the image freq or do I have another 3dB NF degradation?
Ghost
let's say I have an heterodyne front-end. The first mixer will bring both the signal and noise at image freq on the IF freq. This will lead to a ~3dB NF degradation and thus an image rejection filter is required (for other reasons also...). Next comes an IQ demodulator which rejects the image frequency. What about noise? Does the IQ demodulator reject noise at the image freq or do I have another 3dB NF degradation?
Ghost