Cirrus-logic CS42L73 Manuale Utente Scaricare il pdf (Pagina 50)

50 DS882F1

CS42L73

maximum threshold. When the input signal level falls below the maximum threshold, the AOUT volume re-

turns to its original level set in the HP/LO Volume Control register at a programmable release rate. Attack

and release rates are affected by the DAC soft ramp settings and sample rate, Fs. Limiter soft ramp depen-

dency may be independently enabled/disabled using the LIMSRDIS.

Note that the limiter maintains the output signal between the CUSHSPK, CUSHHL, CUSHESL and LMAX-

SPK, LMAXHL, LMAXESL thresholds. As the digital input signal level changes, the level-controlled output

may not always be the same, but always falls within the thresholds.

Recommended settings: Best limiting performance may be realized with the fastest attack and slowest re-

lease setting with soft ramp enabled in the control registers. The CUSHx bits allow the user to set a thresh-

old slightly below the maximum threshold for hysteresis control—this cushions the sound as the limiter

attacks and releases.

Referenced Control Register Location

Limiter Rates ....................... “Limiter Attack Rate HL” on page 107, “Limiter Release Rate HL” on page 107

“Limiter Attack Rate Speakerphone [A]” on page 108, “Limiter Release Rate Speakerphone [A]” on

page 109

“Limiter Attack Rate ESL [B]” on page 111, “Limiter Release Rate ESL [B]” on page 111

Limiter Thresholds............... “Limiter Cushion Threshold HL” on page 108, “Limiter Maximum Threshold HL” on page 108

“Limiter Cushion Threshold Speakerphone [A]” on page 110, “Limiter Maximum Threshold Speaker-

phone [A]” on page 110

“Limiter Cushion Threshold ESL [B]” on page 112, “Limiter Maximum Threshold ESL [B]” on page 112

LIMSRDIS ........................... “Limiter Soft-Ramp Disable” on page 100

Volume Controls.................. “Headphone/Line Output (HL) x Digital Volume Control” on page 101

“Speakerphone Out [A] Digital Volume Control” on page 102

“Ear Speaker/Speakerphone Line Output (ESL) [B] Digital Volume Control” on page 102

“Speakerphone Out [A] Digital Volume Control” on page 102

LMAXx[2:0]

Output

(after Limiter)

Input

LIMRRATEx[2:0]

LIMARATEx[2:0]

Volume

Limiter

CUSHx[2:0]

ATT ACK/ RELEASE SOUND

CUSHION

LMAXx[2:0]

Figure 22. Peak Detect & Limiter

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Cirrus-logic CS42L73 Manuale Utente Pagina 50