- AC coupling for the comparator circuit of the green locking
In order to relieve the power consumption of the RF buffer, ac coupling circuits have been added.
The ac coupling before the buffer amp helps to relieve the power consumption in the chip.
But because of the distortion of the signal (and the limitation of the bandwidth), the output still has some DC (~0.6V).
Therefore, the output is also AC coupled.
Note that the BW pin of BUF634P should be directly connected to -15V in order to keep the bandwidth of the buffer.
The drawings are also uploaded on the green electronics wiki