HP 416A - Page 17

One resultant voltage is applied to the conductor designated A, and
the other resultant , an interval equivalent to If -28 later, is applied to con-
ductor B . The voltage A sinusoid is applied to : ( 1) the RF POWER MONI-
TOR (tuning eye) , which gives visual indication of whether the level of the
incoming voltage is within operating limits , and (2) to a delayed amplitude
volume control amplifier which brings the applied voltage to the level re-
quired for operation of a multiar amplitude comparator in the following
stage. The voltage B sinusoid also is applied, through a delayed automatic
volume control amplifier, to a multiar amplitude comparator.
As the Voltage A sinusoid passes through zero in a negative direction,
the multiar regenerates and a pulse appears at its output (Fig. 6). At a time
corresponding to 71 - 28 degre e s later, the Voltage B sinusoid passes through
zero in a negative direction and the multiar in that channel puts out a pulse.
Thus two pulses the leading edges of which are displaced by a time equiva-
lent to 11 -ze are generated. The two pulses drive a flip - flop.
The meter is connected across the cathodes of two triodes arranged
as a flip - flop circuit . One pulse "flips" the flip ~ flop and the second pulse
"flops " it . The potential between the cathodes of the two tubes in the flip-
flop is an asymmetrical square wave the average value of which is propor-
tional to 8. The meter scales are so calibrated that with a current pro-
portional to e flowing i n the meter circuit, an indication will be given
which i s the square root of tan e .
-8 -