AMBE-1000 Digital Voice Systems, Inc., AMBE-1000 Datasheet - Page 48

• Manufacturer Part Number: AMBE-1000
• Manufacturer: Digital Voice Systems, Inc.

5.
5.1
5.1.1
5.2 Configuration of the A/D-D/A Interface using the Command Interface
The AMBE-1000 is not recommended for new designs.
Please refer to the AMBE-2000/2020 product line.
Important Command Packet Note
A/D - D/A Interface
A/D-D/A Overview
The interface from the analog world of speech and the AMBE-1000™ is typically an
A/D-D/A chip.
preference given to 16 bit linear devices. Additionally, consideration should be given
for signal to noise ratios and filtering characteristics typically built into many such
devices.
spectrum (20-4000Hz) the better the overall system will sound.
The AMBE-1000™ Vocoder Chip operates with a speech data sample rate of 8kHz for
both the A/D and D/A interfaces. This 8kHz data is input and output using a serial port
on the AMBE-1000™.
information) are fully configurable by the user.
signals can be achieved by sending a Command Frame with ID=0x03 to the decoder.
Using Command Frames, the user has complete access to the Serial Port I/O (SIOC)
Register. Additionally, if the A/D-D/A supports a programmable interface, such as the
Lucent CSP1027, the programming sequence can be controlled through this interface
as well.
In order to simplify the process of configuring the interface to the A/D-D/A chip, a
number of preset configurations can be chosen through the C_SEL[2-0] pins shown in
Table 5-A. These preset configurations control signal directions for the interface as well
as the sequence of programming words for the programmable devices, specifically the
CSP1027.
desired then a Command Frame with ID=0x03 should be used. See Section 4.1.14.4
and Table 4-R for an example Command Frame.
If the preset hardware settings are used in the selection of the A/D-D/A interface, care
must be taken if Command Frames with ID=0x03 are subsequently sent to the
decoder, since the information in this control word will supercede any hardware
configuration settings. If one of the hardware configurations is used, and a Command
Frame with ID=0x03 is used later, simply insert the information given in Table 5-A
(SIOC Value, Codec type, Configuration words) into the appropriate fields within the
Command Frame. See Table 4-R for an example.
The A/D-D/A Command packet gives the user the most control of the A/D-D/A interface
as it gives direct control of the Serial I/O register (SIOC) within the AMBE-1000
In many applications this command interface will not be necessary given that a number
of standard configurations are supported through the C_SEL[2-0] hardware interface.
The A/D-D/A Command word also controls some other functions within the AMBE-
1000
accessed then the A/D-D/A serial port interface information must remain consistent.
That is to say, if using the hardware C_SEL[2-0] for interface selection, then the values
in Table 5-A (SIOC Value, Codec Type, Configuration Words) must be repeated in the
A/D-D/A Command frame described in section 4.1.14.4.
such as the VAD enable and echo canceller enable. If these other functions are
The AMBE-1000 is not recommended for new designs.
Generally speaking, the flatter the frequency response over the voice
If a programming sequence other than the one shown in Table 5-A is
Please refer to the AMBE-2000/2020 product line.
Selection of the A/D-D/A chip should be made carefully, with a
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The control signals of this serial port (clocks and framing
page 48
The maximum flexibility of these