Expert Electronics SunSDR2 DX, Руководство пользователя

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SunSDR2 DX User Manual
© 2020 Expert Electronics
ExpertSDR2 SOFTWARE DESCRIPTION
After that change the Frequency parameter, with the 50 Hz step. Frequencies below the
Frequency value are not influenced by the rotator, frequencies above the Frequency value
are rotated.
All voices are unique, having their own AFC, that's why this module should be adjusted
personally by the operator.
Why do you need a phase rotator? Sound vibrations created by human speech organs are
asymmetric by amplitude. They have lots of negative and positive half-waves. It's natural and not
a problem in itself, but some voices may be so asymmetric that compressor and limiter (which
are controlled by peak or RMS signal level) may rapidly lower their levels because of such
asymmetric signal peaks. As a result voice density may drift (vary in real-time), so the voice
doesn't sound natural. Phase rotator changes phase ratios in a signal, leaving the AFC as it is
(it's not an equalizer). Harmonics are shifted in relation to the main frequency, the signal
becomes more symmetrical. Elimination of most asymmetric peaks in the signal lowers the
"aggressiveness" level of the compressor influence, thus voice sounds more natural and dense
at the same time.
Also, rotator gives you a psychoacoustic effect from amplifying the low frequencies and making
your voice sound clearer. It appears because of harmonics time-shift in relation to fundamental
frequencies. After the voice is processed with rotator, you hear harmonics and main frequencies
at different times. It makes harmonics more prominent to our brain, creating a psychoacoustic
effect making a voice clearer.
Pre-proc module enriches
signal with new harmonics imitating a tube preamplifier.
At t ack - this is the period, when the limiter is decreasing volume to reach the level that is
determined by Max Amplit ude.