Modules

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Modules

A module consists of an DSP interface and hardware such as AD, DA controller, etc.. The interface is in principle structured ident for different modules and differs only in the count of bits of a frame used for this module.

That is, the module takes itself from the serial data stream those number of bits or those time-slots which it needs. It possesses further an output, where the data-bits not used are passed on, so that with the bus a so named ''daisy chain'' is formed.

The inputs and outputs are flat-ribbon links like them used with SCSI-2 interfaces, so that a economical and simple connection between modules can be made (see bus-system).

AD/DA - modules

dokumentation in progress, short one as prelimary version

As a first project:

Here high-quality ADDA transducers are planed, which are useable particularly for usage in the studio and live on stage, mastertaping and for performances with the requirement for high dynamics. Further they should also be usable for measuring systems for psychoacustical research etc..

As prototype, ADDA transducers of Crystal are used here, because they are also still affordable, and the evaluation modules can be used. Those have also still the advantage that they also hve a SPDIF/AES-EBU input and output and can be used additionally as stand alone device.

1.: 1 CDB4329 Evaluation Board
2.: 1 CDB5390 Evaluation Board

The installation takes place into a 19'' housings with own power pack. First measurements with the ''Digital-Precision measuring system'' resulted in approx. 108 dB signal-to-noise ratio and also the other values ate very good. A prototype is even in the test phase.

Further applicable are the ADDA board Julia (from the c't-magazine from May July 1996) and appropriate 20Bit ADDA board from the magazine Elektor.

A third source are all ADDA-Interfces whichg where designed for the ''Atari-Falcon" DSP-bus, which is a SSI-Bus and only few affort is need to adapt the interface.

Codecs

dokumentation in progress, short one as prelimary version

These modules are mainly designed for the usesage in the computer (designed as 3-1/2'' modules for the disk-slots) and possesses microphone inputs, stereo-line inputs, stereo-line outputs and headphone outputs. Further an internal interconnecting and volume regulations are possible.

In principle here almost all codecs from crystal could be used, whereby the Crystal codec CS4215, which is used also on the evaluation board EVM56303 von Motorola, was tested. This possesses as the further advantage that it is cascadeable without outside logic and thus a 8-Kanal system per DSP-interface could be easily implemented. To mention here is the CS4216, equipped with 4 DA channels and 2 AD channels and also the surround codecs up to the new 3D-Codecs von Crystal, which mostly hve the same hardware-layout.

16-Kanal 16 Bit DA

dokumentation in progress, short one as prelimary version

A economical solution for 16 DA channels per DSP interface (thus up to 32 channels), particularly for the application for distributed speakers or as audio matrix for sound installations and other, should be made.

Digital Audio Module

dokumentation in progress, short one as prelimary version

As base for these the Crystal chip CS8402 and CS8412 should be used, whereby particularly consideration for the synchronisation should be taken here. Since the DSP board possesses two SSI inputs and independent SSI outputs (Assynchronmodus) it possible to operate these with different of samplerates, whereby the DSP card can make corresponding samplerate conversions. (e.g.: DAT recorders and CD-players digitally mixed).

It is to be noted however that per SSI input only one chip can be active as masters, so that only one SPDIF input can supply the clock. If several SPDIF inputs are available there can usually only synchronizable devices be used. (studio devices in the upper price level).

Here both a SPDIF (Cinch) and a AESEBU (XLR plug) should be available.

As further modules I could think of an ADAT interface, whereby I had found up to now still no documents how this is made, but it work the same as SPDIF-optical interfaces ???

special modules

dokumentation in progress, short one as prelimary version

Free modules are meant as sensor modules, tying up control outputs at the DSP-bus, whereby a base circuit board is created, which takes care of the interface handling of the time-slots from the serial data stream.

These modules particularly target userdefined interfaces for tracker systems, motor controls and interactive installations.

avaiable adaptable modules

dokumentation in progress, short one as prelimary version

Primarily of self-developments was thought, it is however also intended to tie up already available devices.

There are already many commercial devices with the SSI port operates. Here only the DSP bus plug adapters must be created to become compatible.

A first category are all devices build for the ATARI Falcon DSP-port, then there are interfaces with SPDIF in/out, ADDA-modules, a 8-Kanal DA device device and a ADAT interface.

As the second source of devices to be attached are high-quality ones for the NeXT DSP the bus e.g.: Proport from Ariel and also Events electronics builds now external transducers, with 8 channel 20 bit ADDA transducers and SPDIF (status July 97).

Next: Software Up: Hardware Previous: The DSP

HAss.DI Winfried Ritsch - ritsc@iem.kug.ac.at