Phase-detector


Posted on Feb 8, 2013

The output of the detector contains a term related to the cosine of the phase angle. Two signals of equal frequency are applied to the inputs. The frequencies are multiplied together, producing the sum and difference frequencies. Equal frequencies cause the difference component to become de, while the undesired sum component is filtered out. The de component is related to the phase angle by the graph of Fig. 70-2B. At 90°, the cosine becomes zero, while being at maximum positive or maximum negative at 0° and 180°, respectively.


Phase-detector
Click here to download the full size of the above Circuit.

The advantage of using the balanced modulator over other types of phase comparators is the excellent conversion linearity. This configuration also provides a conversion gain, rather than a loss for greater resolution. Used in conjunction with a phase-locked loop, for instance, the balanced modulator provides a very low-distortion FM demodulator. Correct phase sequences (ABC, BCA, or CAB) produce trains of output pulses and illuminate the LED. The output stays low and the LED remains dark for incorrect sequences (BAC, ACB, or CBA) or for phase loss (phase A, B, or C missing).




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

Accelerometer Schematic
Frequency-boundary-detector
simple 100 watt inverter
garageshed alarm
Ionization smoke detector circuit using A5367
Adding 1 PPS and 10MHz Outputs to the Z3801A
Pulsed LC Oscillator
Simple 100W inverter schematic design



Top