Doubly balanced modulator
(4) Looking again at Figure 1-19, one can see that the 3.58 MHz CW subcarrier
is applied to the I and Q modulators through delays. The I signal is delayed 57
degrees from subcarrier and the Q signal is delayed 57 + 90 or 147 degrees away
This corresponds to the I and Q vectors shown in figure 1-18.
Also, the subcarrier is applied to a burst keyer where a portion of the subcarrier
is inserted onto blanking for use as a color sync.
e. Color synchronization signal.
Since the subcarrier is suppressed at the
colorplexer, the local 3.58 MHz oscillator at the receiver must be accurately
transmitter. In order to maintain these two oscillators in phase, a short burst of
horizontal scanning line.
gating circuit which is turned on by burst keying pulses derived from a device
This device is also locked in with the station