Measuring the transmit frequency.

The frequncy measuring is done by using a 12bit binary counter (74LV4040).
The output is then fed to the microcontroller section for further processing.
The input of the prescaler is driven by an LVDS line receiver.These driver provide 3V output signals and have a differential sensitivity level of around 100mV and have a 400Mhz bandwidth.
The datasheet can be found here.

Measurement Bridge : Modifications

In order to adjust the frequency response of the voltage divider the capacitive leg was splitted into 2 dividers.
The first is formed by C2 and C1 + C32. The secondary divider is formed by C30 and C3.
This construction makes it easier to use a low capacitance trimmer in adjusting for a flat response.

To compensate for the error caused by the inductive part of R4 a small capacitor (C33) was added in parrallel with R6.