D6571E Просмотр технического описания (PDF) - Unspecified

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D6571E

EASYTAD™ Chip for an All- Digital Telephone Answering Machine with Flash Memory Interface

Unspecified 

D6571E Data Sheet

Minimum Level Emin - minimum input signal energy

level that is amplified to optimum value Eopt. For

signals greater than Emin the AGC gain is calculated as

G = Eopt/Einput

Maximum gain Gmax = Eopt/Emin

Gain Threshold Level Eatt - signals smaller than Emin

and larger than Eatt are amplified by maximum gain Gmax

Silence Threshold Level Es il - signals lower than Esil

are considered silence. The gain for such signals = 1.

Signals greater than Esil but smaller than Eatt will be

amplified by the gain linearly growing from 1 to Gmax.

Hold Time Thold - this parameter the hold time of the

AGC gain during the pause in the speech. The intent of

the decay time is to “bridge” the gaps between syllables

and words resulting in stable gain.

Decay Time Tdec - this parameter defines the rate by

which the gain increases after hold time elapsed.

Default values of the parameters are presented in the

following table.

Parameter

Eopt

Emin

Eatt

Esil

Thold

Tdecay

Default

Value

(decimal)

4 dB

22 dB

36 dB

46 dB

100

10

Default

Value (hex)

0004

0016

0024

002E

0064

000A

Default Value

(Physical

meaning)

- 1 dBm*

- 19 dBm*

- 33 dBm*

- 43 dBm*

2.0 sec

1.0 sec

* - Calculated as (3 - Value) dBm

G

Gain function

1

0

E sil

Eatt

Emin

Eopt

Submode 011 = HPF configuration

Submode 3 enables low pass filter (enabled by default).

The performance of this mode is the same in case of

“cold” and “warm start.”

Submode 100 = FSK configuration

This submode allows to control sensitivity of the FSK

detector.

7) Volume Control (Test Mode = 1000)

This mode allows setting of the signal level playing to

the Codec. The default value is 0 dB and the volume

may be set in 2 dB steps from -42 to +16 dB or may be

muted.

This command allows the HOST to read the current

volume setting without changing it (bit 7 = 0), or set new

volume (bit 7 = 1) specified in bits 0 through 4. The

status will reflect the current volume setting.

The Volume Control command can be issued in Record,

Playback, Voice Prompt and Line Monitor Mode without

interrupting these modes. When issued in one of these

modes, the status will be the status of the current

operating mode. Therefore, current volume setting can

not be read during operating modes.

The performance of this mode is the same in case of

“cold” and “warm start.”

8) Storage Configuration (Test Mode = 1001)

This mode allows to define necessary space of the

General Purpose Storage. GPS can occupy up to 16

sectors 3200 bytes each sector. By default GPS is not

available (0 sectors).

9) Program DTMF, VOX, CPT, CAS Sensitivity (Test

Mode = 1010)

The mode allows independent setting of the sensitivity

of the DTMF detection, CAS detection, VOX detection,

and Call Progress Tone detection. The default

sensitivity level is 0 dB and each sub-system may be

adjusted in 2 dB steps from -16 dB (most sensitive) to

+42 dB (least sensitive)or can be disabled.

This command also allows the HOST to read the current

sensitivity setting of the selected signaling subsystem

(specified in bits 6 - 7) without changing this setting (bit

5 = 0). When bit 5 = 1, the command sets the new

DS6571E.2

DSP GROUP, INC., 3120 SCOTT BOULEVARD

21

SANTA CLARA, CA 95054 PH: 408 986-4300 FAX: 408 986-4490

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