SL5067
than the picture carrier itself. Thus if the picture carrier level is
reduced by using a resistor on pin 3 (mod index set), the level
of the sound subcarrier will not change. This should be
remembered when setting up a modulator to give the desired
modulation index and vision/sound carrier ratio.
device into these modes, it should be noted that the SL5067
will not perform to full SECAM specifications.
Use of AM sound may produce sound–in–vision
interference at higher modulation depths. It should be
possible, however to AC couple in modulated audio. If this is
attempted, the sound tank circuit on pins 15 and 16 would not
be required. The modulated audio signal should be fed into the
Audio input pin (pin 17) via a 470nF capacitor.
The FM/AM select pin can be used as a gain control pin, but
will not switch the device between FM and AM modes.
POSITIVE MODULATION
Several references are made in the text to positive video
modulation and AM sound. Whilst it is possible to switch the
GEC [ GENERAL ELECTRIC COMPANY ]
