Re: Building Blocks for an FM Band Receiver
Thank you for your valuable input. I updated the block diagram accordingly. Regarding the BPF before the RF amplifier, I implemented actually this BPF based on a design I created using Elsie application. I checked its insertion loss using the VNA, and it is around 4-8 db (not flat across the FM band).
Is it OK to get this attenuation and then amplify the received signal? Won't this reduce the sensitivity of the receiver?
For the mixer, I am planning to use an SA612AD that I purchased. Is this a suitable choice?
Regarding the quadrature demodulator, reading about it, seems that it can as well be implemented using a mixer feeding it with the signal, and its 90deg shifted and take the output of the mixer through a LPF. Would it be ok to use the same type of mixer for this, or should I look for a ready made chip to perform the demodulation?
A question in my initial post was regarding impedance matching. Not sure that it was addressed yet. My understanding is that impedance matching is very important in the front end to improve the received weak signal power transfer.
The BPF is design for 50 ohm input impedance. Measuring the antenna impedance in the FM band is showing a Z ranging from (20-j1000) @ 87MHz to (32-j767) @ 108MHz.
How can I match this range to the fixed 50 ohm input impedance of the BPF?