WM8978GEFLSLASHV datasheet(34/78 Pages) WOLFSON

номер детали	WM8978GEFL/V

подробное описание детали	STEREO CODEC WITH SPEAKER DRIVER

PDF	78 Pages

Scroll/Zoom	100%

производитель	WOLFSON [Wolfson Microelectronics plc]

домашняя страница	http://www.wolfsonmicro.com

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WM8978

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PP Rev 1.7 January 2005

Figure 13 DAC Digital Limiter Operation

The limiter has a programmable upper threshold which is close to 0dB. Referring to Figure 13, in

normal operation (LIMBOOST=000 => limit only) signals below this threshold are unaffected by the

limiter.

Signals above the upper threshold are attenuated at a specific attack rate (set by the

LIMATK register bits) until the signal falls below the threshold. The limiter also has a lower threshold

1dB below the upper threshold.

When the signal falls below the lower threshold the signal is

amplified at a specific decay rate (controlled by LIMDCY register bits) until a gain of 0dB is reached.

Both threshold levels are controlled by the LIMLVL register bits. The upper threshold is 0.5dB above

the value programmed by LIMLVL and the lower threshold is 0.5dB below the LIMLVL value.

VOLUME BOOST

The limiter has programmable upper gain which boosts signals below the threshold to compress the

dynamic range of the signal and increase its perceived loudness. This operates as an ALC function

with limited boost capability. The volume boost is from 0dB to +12dB in 1dB steps, controlled by the

LIMBOOST register bits.

The output limiter volume boost can also be used as a stand alone digital gain boost when the limiter

is disabled.

WM8978GEFL/V датащи(PDF) 34 Page - Wolfson Microelectronics plc