| 摘要 |
<p>A phase detector for generating a measurement signal indicating the extent to which the actual distance ( tau ) between the flanks of data pulses generated for serial data transmission and the detection times determined by a detection clock differs from a required distance (Tg). The phase detector generates on every flank of the data signal a first and a second puls, by means of two D-flipflops (11,12) controlled by the detection clock.
<??>The pulsewidth of the first pulse is equal to the detection clock cycle time T. The pulsewidth tau of the second pulse is equal to the distance between the flank of the data-signal and the next following flank of the clocksignal. The amplitudes of the first and second pulses are adjusted and the adjusted first and second pulses are then fed to a differential amplifier (16). The adjustment is such, that the ratio between the amplitudes of the first pulses and the amplitudes of the second pulses is equal to Tg/T, so that the average value of the output signal of the differential amplifier is a measure of the difference between the actual distance tau and the required distance Tg. </p> |
