Modulator with Power Supply - MT-27P (channels 1-69 & S9-S17)

Modulator view

...and the view after removing the flap covering main part

Top view. Push-buttons "+" and "-" serve to settle output channel, with the left side pot underneath the proper deviation of sound subcarrier is set, and the right lower corner pot sets RF output level of the modulator.

Termination load and mounting screws included

Output level adjustment enables to match the level to other signals within an installation, also concerning other possible connected in series modulators.

50 kHz is the standard modulation assumed for input audio signal of 0.775 V RMS. The adjustment of deviation ensures to level the deviation when an audio signal differs from the norm. The ultimate standard deviation can be obtained within range of 0.150-0.775 V . Correct adjustment is essential for equal volume levels on individual TV channels. Switching on the power having pressed one/two of the keys on the modulator allows to set some other parameters.

The standard depth of video modulation is 75%, however sometimes it can be useful to change it a little, e.g. when a source generates alphanumeric characters a bit exceeding proper limit. The possibility of setting video modulation factor within +/-6% enables correction in such cases, optimizing the signal quality. In practice it is seen as no great change of brightness and contrast of the picture, e.g. of that characters. Generally, when the original and converted by the modulator picture is of regular quality (no overmodulation), and sound is clear, no correction is needed.

The standard depth of video modulation is 75%, however sometimes it can be useful to change it a little, e.g. when a source generates alphanumeric characters a bit exceeding proper limit. The possibility of setting video modulation factor within +/-6% enables correction in such cases, optimizing the signal quality. In practice it is seen as no great change of brightness and contrast of the picture, e.g. of that characters. Generally, when the original and converted by the modulator picture is of regular quality (no overmodulation), and sound is clear, no correction is needed.

Changing a little output frequency one may attempt to eliminate interferences coming from neighboring channels, when they are fixed in the system. Making offset of the output modulator's frequency there is a chance to solve that problem. The possible range is +/-2.5 MHz at 250 kHz intervals. Generally, when the signals within installation are of good quality, that feature is not used.