WM8945ECSSLASHR datasheet(36/169 Pages) WOLFSON

36 / 169 page

WM8945

Production Data

PD, May 2011, Rev 4.1

To determine the characteristics of the loudspeaker in an application, a test signal is applied to the

target application. A reference microphone is positioned in the normal acoustic path of the

loudspeaker, and the received signal is analysed to determine how accurately the loudspeaker has

reproduced the test signal.

5-BAND EQ

ReTuneTM

5-band EQ

Signal Enhancement Block 2 (SE2)

The 5-band EQ is part of the SE2 block. This function allows 5 frequency bands to be controlled. The

upper and lower frequency bands are controlled by low-pass and high-pass filters respectively. The

middle three frequency bands are notch filters. The cut-off / centre frequency of each filter is

programmable, and up to 12dB gain or attenuation can be selected in each case. The 5-band EQ is

enabled using the SE2_5BEQ_L_ENA register bit defined in Table 14. For the derivation of the other

associated registers, refer to the WISCE software.

Typical applications of the 5-band EQ include the selection of user-preferences for different music

types, such as ‘rock’, ‘dance’ or ‘classical’ EQ profiles.

DYNAMIC RANGE CONTROL (DRC)

DRC

Signal Enhancement Block 3 (SE3)

The Dynamic Range Control (DRC) forms the SE3 block. The DRC provides a range of compression,

limiting and noise gate functions to support optimum configuration for recording or playback modes.

The DRC is configured using the control fields in registers R29 to R35 – see “Dynamic Range

Control”.

SIGNAL ENHANCEMENT REGISTER CONTROLS

The SE1 ‘enable’ bits are described in Table 13. Note that other control fields must also be

determined and written to the WM8945 using WISCE™ or other tools. The registers described below

only allow the sub-blocks of SE1 to be enabled or disabled.

Note that it is not recommended to access these control fields unless appropriate values have been

written to the associated bits in registers R65 to R95.

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