1-32
Figure 1-21B.—TX-TR system operation (addition).
Now, with the TX in the same position (75º), the TDX rotor is turned to 30º (view B). The angle
between the TDX stator field and R2 is then increased by 30º. This appears to the TR as an additional
rotation of the TDX stator field. In transmitting the TX signal to the TR, the TDX adds the amount its
own rotor has turned. The TR rotor now turns to 105º. Thus, the equation 75º + 30º = 105º is solved.
Q-34. In a TDX system when does the TR rotor follow the TX rotor exactly?
Q-35. What is the angular position of a TX rotor when it is pointing toward the S1 winding? (Hint.
Remember synchros are labeled counter clockwise from 0º.)
Q-36. In a TDX system with standard synchro connections, the TX rotor is at 120º and the TDX rotor is
at 40º. What position will the TR indicate?
Q-37. What connections in a TDX system are reversed to set up the system for addition?
TX-TDR-TX System Operation (Subtraction)
As we previously explained, the differential receiver differs chiefly from the differential transmitter
in its application. The TDX in each of the previous examples combined its own input with the signal from
a synchro transmitter (TX) and transmitted the sum or difference to a synchro receiver (TR). The synchro
receiver then provided the system's mechanical output. When the differential receiver (TDR) is used, the
TDR itself provides the system's mechanical output. This output is usually the sum or difference of the
electrical signals received from two synchro transmitters. Figure 1-22 shows a system consisting of two
TXs (No. 1 and No. 2) and a TDR connected for subtraction.
Figure 1-22.—TX-TDR-TX system operation (subtraction).
