Sony DTC-A6 Guide to the Serial Copy Management System, Applying the principle of human hearing

Applying the principle of human hearing

The SBM function applies the principle of human hearing in the reintegration of signal information. The auditory range of the human ear is generally considered to be 20 Hz to 20 kHz; hearing sensitivity, however, shows greater sensitivity to the range between 3 kHz and 4 kHz, and lower sensitivity to frequencies above and below this range. This principle applies also to quantizing noise as well. By reducing quantizing noise in this particular range, signals can be recorded to produce more expansive sound than is possible by a uniform reduction of noise over the entire audible range.

Noise-shaping filter

The SBM function uses a noise-shaping filter (see Fig.

B)with a frequency response similar to that of the human ear to reduce quantizing noise within the most sensitive frequency range, and to feed back the quantizing error (that is normally lost) back to the input signal, re-integrating the low-end bit information with the high-end bit information (see Fig. A).

Fig. A

24-bit information	/	Noise-shaping	/	16-bit SBM
input		filter		output

Fig. B shows the improvement in the quantizing noise level when the SBM switch is on (theoretical values). Given a noise level of 0 dB when the SBM switch is off, the improvement in noise level for sampling frequencies lower than 3 kHz exceeds 10 dB when the SBM is activated.

Fig. B

Additional Information

Guide to the Serial Copy Management System

This deck uses the Serial Copy Management System, which allows only first-generation digital copies to be made of premastered software via the deck’s digital input jack. An outline of this system appears below:

1You can record from digital program sources (CDs, premastered MDs or DATs) onto a DAT or recordable MD via digital input jack on the DAT or MD deck. You cannot, however, record from this recorded DAT or MD onto another DAT or recordable MD via the digital input jack on the DAT or MD deck.

Playing	CD player
DAT deck		MD deck

Digital output jack

Optical cable or coaxial digital connecting cable

Digital input jack

DAT deck or

Recording

MD deck

v

First-generation DAT or MD

DAT or MD recorded via digital-to-digital

vconnection

Playing	DAT deck or
	MD deck

25

20

Noise 15 level 10 (dB) 5

0

-5

-10

20

SBM

ON

SBM

OFF

50 100 200 500 1k 2k 5k 10k 15k

Sampling frequency (Hz)

Digital output jack		Line (analog) output jack
Optical cable or		Audio connecting
coaxial digital
		cord
connecting cable
Digital input jack		Line (analog) input jack
Recording	DAT deck or
	MD deck

The SBM function operates only during recording. The improved sound produced by the SBM function, however, can be enjoyed during playback, regardless of the SBM switch position or the DAT deck being used.

(Continued)

21EN

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