dexing
Newbie level 6
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Im doing a design of front end of RF receiver. I have designed the LNA, mixer and VCO according to my own value by referring to the tutorial from rfic.co.uk. The tutorials are CMOS Gilbert Cell Mixer, CMOS Common Source LNA and LC Oscillator Tutorial. The simulation of the individual design has no problem but problem occurs after combining them.
The output of mixer after a bandpass filter was not the difference between LNA & VCO. The output is still fine with LNA alone connected to the mixer. I was trying to input 2.5GHz for LNA and 2.25GHz for VCO. But the output was 4.097GHz which is the same as measured in LNA but differed from my input of 2.5GHz. I found that the oscillator mode need to be enabled for vco simulation but not for LNA. In fact I dun really understand the settings for simulation.
Im very new in RF and has never done anything similar. I wish to get some advices through this forum...
Thanx
Im doing a design of front end of RF receiver. I have designed the LNA, mixer and VCO according to my own value by referring to the tutorial from rfic.co.uk. The tutorials are CMOS Gilbert Cell Mixer, CMOS Common Source LNA and LC Oscillator Tutorial. The simulation of the individual design has no problem but problem occurs after combining them.
The output of mixer after a bandpass filter was not the difference between LNA & VCO. The output is still fine with LNA alone connected to the mixer. I was trying to input 2.5GHz for LNA and 2.25GHz for VCO. But the output was 4.097GHz which is the same as measured in LNA but differed from my input of 2.5GHz. I found that the oscillator mode need to be enabled for vco simulation but not for LNA. In fact I dun really understand the settings for simulation.
Im very new in RF and has never done anything similar. I wish to get some advices through this forum...
Thanx