peb2265 ETC-unknow, peb2265 Datasheet - Page 14

• Manufacturer Part Number: peb2265
• Description: Channel Codec Filter With Iom -2 Interface Iom -2 Sicofi -2
• Manufacturer: ETC-unknow

Semiconductor Group
2.2
Figure 3
The IOM-2 – SICOFI-2 bridges the gap between analog and digital voice signal
transmission in modern telecommunication systems. High performance oversampling
Analog-to-Digital Converters (ADC) and Digital-to-Analog Converters (DAC) provide the
required conversion accuracy. Analog antialiasing prefilters (PREFI) and smoothing
postfilters (POFI) are included. The connection between the ADC and the DAC (with
high sampling rate) and the DSP, is done by specific Hardware Filters, for filtering like
interpolation and decimation. The dedicated Digital Signal Processor (DSP) handles all
the algorithms necessary e.g. for PCM bandpass filtering, sample rate conversion and
PCM companding. The IOM-2 Interface handles digital voice transmission,
IOM-2 – SICOFI-2 feature control and transparent access to the IOM-2 – SICOFI-2
command and indication pins. To program the filters, precalculated sets of coefficients
are downloaded from the system to the on chip coefficient ram (CRAM).
2.3
The IOM-2 Interface consists of two data lines and two clock lines. DU (data upstream)
carries data from the IOM-2 – SICOFI-2 to a master device. This master device performs
the
24 IOM-2 – SICOFI-2's. DD (data downstream) carries data from the master device to
the IOM-2-SICOF-2. A frame synchronization clock signal (8 kHz, FSC) as well as a data
clock signal (2048 kHz or 4096 kHz DCL) has to be supplied to the IOM-2 – SICOFI-2.
The IOM-2 – SICOFI-2 handles data as described in the IOM-2 specification for analog
devices.
Command
Indication
Analog out
Analog in
interface
IOM
IOM
®
®
-2 – SICOFI
-2 Interface
Signaling
between
DAC
ADC
the
®
-2 Block Diagram
PCM-backplane,
IOM2-Interface
IOM2-Bus
DSP
14
the
IOM
®
-2 – SICOFI
Controller
Signaling
DAC
ADC
®
and
-2 Principles
PEB 2265
iom3.wmf
1997-07-01
Command
Indication
Analog out
Analog in
up
to