BSS Audio DPR-901ii, Руководство пользователя и инструкция по эксплуатации

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DPR-901ii
describe voltage levels, although strictly it only applies to 600 ohm
circuits. We recommend you use dBu instead.
dBu or dBv The addition of ‘u’ or ‘v’ after dB indicates an absolute scaling for the dB
ratio. 0dBu (or 0dBv) = 778mV or 0.778 volts, and it has no regard to
power or impedance. dBu and dBv are widely used for expressing signal
voltages in modern audio equipment, where output impedances are low,
and input (load) impedances are much higher.
dBV The same as for dBu above, except 0dBV = 1.0 volts. To convert dBV to
dBu, simply subtract 2.2dB.
DISTORTION
Refers to any modification of a signal which produces new frequency
components not present in the original. Harmonic distortion refers to
added components that are overtones to the fundamental frequency.
Intermodulation distortion creates sum and difference frequencies which
are highly objectionable, because they’re not harmonically related to the
original.
EXPAND Making a signal bigger in proportion to its magnitude. Normally the
amount of expansion is described with a plain numerical ratio (eg. 2:1)
or in decibels (which express the same ratio), eg. 6dB. Some common
ratios are:
3dB: 1.4:1
6dB 2:1
10dB 3:1
20dB 10:1
26dB 20:1
30dB 30:1
See COMPRESS (above) for an explanation of threshold and below
threshold expansion.
FREQUENCY The repetition rate of a waveform. The unit of frequency is Hz, and 1
cycle per second is equal to 1Hz. The audio band is generally regarded
as spanning the frequencies between 20Hz and 20,000Hz (20kHz).
FREQUENCY RESPONSE
Refers to the equipment’s relative gain, compared to frequency. Gener-
ally expressed as +/- a certain number of dB’s from 20Hz to 20kHz.
HEADROOM The amount in dBs, above the normal operating level that can be used
before serious distortion commences.
HF High Frequencies, generally 800Hz or 3500Hz up to 20,000Hz.
IMPEDANCE The AC equivalent of resistance. Impedance is measured in ohms, and
indicates the amount of drive current required for an input, or the drive
capability of an output, at a given signal level.
LEVEL The amplitude of a signal, measured in volts or decibels.