The images below (and their sources) show the quad dishes of the Apollo Deep Space High-Gain Antenna and the Russian B529 ground station tracking antenna.
From NASA Technical Note TN D-6723 Apollo experience report: S-band system signal design and analysis which I found here
The high-gain antenna consists of an 11-inch-diagonal wide-beam horn flanked by an array of four 31-inch-diameter parabolic reflectors, as shown in figure 5. Transmitting beam widths of 40.0°, 11.3°", and 4.4° are selectable by manual switch. Reception and transmission gains corresponding to these beam widths are listed in table I. The antenna tracks by using electronic conical scan where the angle-tracking information is encoded as amplitude modulation (AM) on the phase-modulated signal received from earth. This error information is extracted within the USB equipment by a narrowband coherent amplitude detector and routed back to the antenna system, thereby providing angular displacement control.
My understanding of or at least theory of how this actually worked is written in this (now-deleted) comment:
At least the part of the signal from each of the four antennas is separately amplified, detected and changed to a DC signal strength level, and then the ratio of the four signal strengths is used to determine the direction and magnitude of the pointing error and used for steering and tracking.
and it's how I also think the old Soviet quad parabola tracking dishes worked, but I'd like to read further. However I am not sure. Is it possible to understand exactly how this worked?
Question: How were the signals from quad dishes of Apollo Deep Space High-Gain Antenna or Russian B-529 processed for local control of tracking?