the two OpAmps of U8 receive the sine wave from TX generator and convert to square wave for control 3 parts of quad bilateral switch U2.
The mesh consisting of C23, R43 + VR3, and C24 cause some delay of the square wave for switching (U8 - pin 1) will respect to the other square signal existing in U8 - pin 7.
VR3 are used to the fine adjust angle of this delay and thereby enable a RX signal sampling at different times to the first two low pass filters of U3.
The mesh consisting of C23, R43 + VR3, and C24 cause some delay of the square wave for switching (U8 - pin 1) will respect to the other square signal existing in U8 - pin 7.
VR3 are used to the fine adjust angle of this delay and thereby enable a RX signal sampling at different times to the first two low pass filters of U3.
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