M65818AFP datasheet(27/39 Pages) RENESAS

27 / 39 page

M65818AFP

Rev.1.00, Sep.04.2003, page 27 of 38

• Operating time of Soft Mute

Total steps from Maximum value(10100b/11111111b) to Minimum value(00000b/00000000b)

(128steps/1 index) × (20index (10100b-10000b)) +256steps = 2816steps.

The transition term of up and down depend on 2fso clock.

Therefore, in case of fso=48kHz, T=1/2fso=10.416µsec/step, transition term are following.

From Maximum value (10100b/11111111b) to Minimum value (00000b/00000000b) : 2816T=29.333msec.

From 0dB value (10000b/10000000b) to Minimum value (00000b/0000000b) : 2304T=24msec

6dB transition term (when over 00000b/10000000b (=-96dB) value ) : 128T=1.333msec.

• Soft Attenuate.

Transition from older Gain Attenuation to newer Gain Attenuation always operates with Soft Mute function.

For example, in case of Gain1 > Gain3 > Gain2, transition process is shown below.

At first, GAIN1 is operated, then second, GAIN2 is operated.

In case that GAIN2 is operated faster than GAIN1 of transition completion (refer to "A" situation in figure)

GAIN1 is ignored and data approaches at GAIN2.

Further, GAIN3 is operated faster than GAIN2 of transition completion( Refer to "B" or "C" situation in figure),

GAIN2 is ignored and data approaches at GAIN3.

(GAIN1)

(GAIN3)

(GAIN2)

1.0

-1.0

Gain

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