| commit | ab061b633c24f8d307e4910f91dc72ba297f962e | [log] [tgz] |
|---|---|---|
| author | ryanrocket <ryan.wans@icloud.com> | Wed Feb 02 17:06:43 2022 -0500 |
| committer | ryanrocket <ryan.wans@icloud.com> | Wed Feb 02 17:06:43 2022 -0500 |
| tree | be79e0e5606ab208bcb61d8bab7332531a68c6ad | |
| parent | d8b955171643a7e1b2b1dab2440186700e5450a7 [diff] | |
| parent | 84206cefdf5c922b84356933b64e132168329e1e [diff] |
Merge branch 'main' of https://github.com/ryanrocket/caravel_automatic_gain_control into main
Automatic Gain Control project submission to the Google-funded Open-MPW program.
Automatic Gain Control is a feedback loop used in receiver architectures for signal amplification. Its primary usage is in environments where the relative signal strength is variable and could pose oversaturation on the receiving amplifier, such as that of radar recievers.
In order to achieve optimal amplification from the LNA, a digitally-stepped attenuator is placed preceeding the LNA to attenuate any signal over a specific saturation threshold. After the signal is amplified, the output is coupled into a power detector circuit, which is then fed into an ADC and back into the DSA to drive the signal attenuation. Once the power detector is able to realize oversaturation at the output, it will drive the DSA to further attenuate the signal, reducing the power output.
This AGC chip is part of a larger project; an FMCW radar for robotic applications. An AGC is paramount in radar applications where the distance between the antenna and the object for detection is unknown. If the object is further away than anticipated; amplification of the received signal will be needed. If it's too close; attenuation may be necessary to prevent ‘blowout’ of the reciever architecture.
This pseudo-differential DSA consists of 4 fixed-attenuation stages, each with SPDT transmission gates to either pass the input signal into the resistor or through to the next stage. The attenuation increases in each stage.
Fully differential common-source amplifier with active loads and tail current mirror.
Takes the differential input and creates a self-mixed DC current, which gets mirrors and converted into a voltage.