AK2308LV_05 Datasheet, PDF (11/31 Pages) Asahi Kasei Microsystems – SPEECH CODEC for Digital Key telephone

ASAHI KASEI
[AK2308LV]
2-2-2 16 bit Linear PCM data mode
In this mode the 16 bit linear PCM data are interfaced to the outside. This mode is useful to compress/extend the PCM
data using much higher compress rate algorithm than u/A -law algorithm by the external DSP. The AK2308LV CODEC
operates at 14bit accuracy, thus the least 2 bits are output as fixed value.
2-2-2-a Signals
- Frame Sync signal (FS)
8kHz reference signal which is as sa me as in u/A-law PCM data mode. “H” level pulse width of the FS should be 1 clock
period as same as in the short frame PCM mode.
- Bit Clock (BCLK)
BCLK defines the PCM data rate. BCLK can be varied from 128kHz to 2.048MHz by 64kHz step which is different from
in the u/A-law PCM data mode.
- PCM data output (DX)
DX is an output signal of 128Kbps linear PCM data. The data is synchronized to the BCLK which determines the data
rate. In the period which the PCM data is not occupied, the DX pin turns to Hi -impedance output.
- PCM data input (DR)
DR is an input signal of 128Kbps linear PCM data. The data is clocked by the falling edge of the BCLK and fed into
the D/A block.
16bti Linear Frame format
125us (8KHz)
FS
BCLK
MSB First
DX
Hi-Z
1 2 3 12 13 14
Hi-Z
MSB First
DR
*
1 2 3 12 13 14 * *
*
Hi-Z
1
*
1
2-2-3 AK130 B1/B2 Mode
These modes are for connecting the PCM interface to AK130, AKM ’s TCM( ping-pong ) transceiver for PBX/KTS
system.
The PCM data format is A-law or u-law which can be selected by the register. The AK130 B1 mode interfaces the data
to B1 channel, one of the B channel which AK130 provides, and the AK130 B2 mode interfaces the data to B2 channel.
2-2-3-a Signals
- Frame Sync signal (FS)
___
Please feed the FS signal which is generated by AK130.( F0o , pin#3 )
- Bit Clock (BCLK)
BCLK defines the PCM data rate. Please use 2.048MHz clock which is generated by AK130.( E2o,pin#5 )
- PCM data output (DX)
DX is an output signal of 128Kbps linear PCM data. Please connect to the PCM data input pin of AK130. ( DSTi,pin#11 )
- PCM data input (DR)
DR is an input signal of 128Kbps linear PCM data. The data is clocked by the falling edge of the BCLK and fed into
the D/A block. Please connect to the PCM data output pin of AK130. ( DSTo,pin#6 )
MS0227-E-01
11
2005/12