GPS Receiver SFDR Too High
时间：04-05
整理：3721RD
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Hi,
I'm designing a receiver for a software defined GPS project. I have entered my current signal chain in ADIsimRF and have attached a screenshot below. I am simulating with a -160dBm input which is the lowest possible signal that can be decoded. The first stage is an active antenna with 40dB gain and the part numbers for the rest of the chain are in the screenshot.
The SFDR is terrible, it's actually negative. I imagine my gain structures wrong and I need devices with a higher IIP3 but everything I've seen is in the same ballpark.
I'm approaching this from a strong DSP and reasonably competent low frequency analogue perspective but have never done any microwave circuits before so I'm still getting to grips with the terminology.
Would anyone be able to tell me where I am going wrong and a better way to approach this?
Thank you in advance for any help you could provide,
Tom
I'm designing a receiver for a software defined GPS project. I have entered my current signal chain in ADIsimRF and have attached a screenshot below. I am simulating with a -160dBm input which is the lowest possible signal that can be decoded. The first stage is an active antenna with 40dB gain and the part numbers for the rest of the chain are in the screenshot.
The SFDR is terrible, it's actually negative. I imagine my gain structures wrong and I need devices with a higher IIP3 but everything I've seen is in the same ballpark.
I'm approaching this from a strong DSP and reasonably competent low frequency analogue perspective but have never done any microwave circuits before so I'm still getting to grips with the terminology.
Would anyone be able to tell me where I am going wrong and a better way to approach this?
Thank you in advance for any help you could provide,
Tom
