Resolver-signal demodulator for variable frequency excitation signals

An alternative approach to implement the resolver-signal demodulator is presented in this paper. The realization technique utilizes the phase shift behavior of an all-pass filter connected with a designed logic circuit to generate the control signals for sub-circuits. The proposed demodulator produces two output signal voltages, which are the sine and cosine envelopes of resolver-shaft angle without low-pass filter circuit. Experimental results verifying the performance of the proposed circuit are closely agreed with the expected values. © 2014 ISSN 1881-803X.