Phase modulation and complex SQUID circuits

The possibilities of using amplitude and phase demodulation in radio-frequency SQUIDs are analyzed. It is shown that at large values of the (k-squared)(Q) parameter the phase demodulation circuit makes it possible to obtain a greater sensitivity due to a wider signal characteristic. But in the usual case, when the coefficient of coupling (k) of the interferometer with the cavity can be varied, the phase demodulation circuit does not offer any advantages compared with the conventional amplitude-demodulation SQUID circuit.