This is the DC gain and BW analysis of the difference amplifier module that shabaz designed for a Direct Conversion Receiver.
I'm searching for these points:
- gain at 1 kHz (approx. mid of bandwidth)
- -3 dB frequencies
I 'll use Vrms values in the post - common for audio circuits. When measuring one of the differential channels, I tied the other to ground.
Specs:
- Gain: ~10 dB
- Bandwidth (-3 dB): ~30 Hz to 40 kHz (approximate)
Measurements:
IN1: gain (1 kHz): 9.228 dB, bw (-3 dB): 30 Hz - 80 kHz
IN2: gain (1 kHz): 9.345, bw (-3 dB): 27 Hz - 80 kHz
shabaz published the KiCad project on GitHub, including simulation. You could load it into KiCad and check if the small signal state simulation and my measurements match ...
For all blog posts in this series, click here
spreadsheet: differenceamp.zip
