Phase detector

Provides a DC output voltage proportional to the difference in phase between two RF input signals. A double-balanced mixer can perform as a phase detector when the LO and RF signal inputs are at the same frequency.

DC offset

The small amount of voltage present at the output when there should actually be 0V, such as when only one input is present, or when the two RF input signals are 90° out of phase. This offset voltage is due to slight mismatches in the diodes and/or imperfect balance in the transformer winding.

Maximum DC output

Originates from a phase detector, and occurs when the RF and LO signals are in phase or 180° out-of-phase.

Figure-of-merit, M

A method for defining the efficiency of a phase detector. It is the ratio of maximum DC output voltage, in mV, divided by the RF power in dBm.

Frequency range spec refers to the frequency range of operation of the phase detector, such that the figure of merit decreases to 75% of its mid-band value.

Scale factor

The phase detector output measured in mV / ° in the approximate linear range of operation, 0 to 57.3°, or 1 radian.

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