6-8 Technical Data
The stereo encoder is calibrated so that 100% left or right modulation will provide 100% modulation of the stereo
composite signal, including pilot tone, but excluding any SCA subcarriers. The pilot tone stereo system has an
interleaving property, which means that the stereo composite modulation is approximately equal to the higher of
the left or right channels.
Because the pilot tone is phase-synchronous with the stereo subcarrier, the composite modulation will actually
increase about 2.7% when the modulation is changed from pure single-channel to L+R modulation while the peak
audio level is held constant.
When the 5950’s left/right analog output is switched to FLAT, a de-emphasis filter is inserted between output of
the 5950’s audio processing and its line output. Thus, as the frequency of the Test Tone is changed, the level at the
5950’s line output will follow the selected de-emphasis curve. In most cases, the pre-emphasis filter in the driven
equipment will undo the effect of the 5950’s internal de-emphasis, so the 5950’s output level should be adjusted
such that the tone produces 100% modulation of the transmission link as measured after the link’s pre-emphasis
filter. At 100Hz, switching the de-emphasis out or in will have negligible effect on the level appearing at the 5950’s
left and right audio outputs. You can adjust the frequency and modulation level of the built-in line-up tone. You
can use the HTML5 PC connection, or the opto-isolated remote control interface ports to activate the Test Tone.
Built-in Calibrated Bypass Test Mode
A BYPASS Test Mode is available to transparently pass line-up tones generated earlier in the system. It will also
pass program material, applying no gain reduction or protection against overmodulation. It can transparently pass
any line-up tone applied to its input up to about 130% output modulation, at which point clipping may occur.
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