DSP ALGORITHMS is a proud member of Analog Devices Alliance program. Adding new complex function, such as multiple microphone audio conferencing for instance, to existing or new products can be a daunting undertaking. To start from scratch, it needs thorough understanding of the hardware and software requirements of this new function. Without the proper experience designing products with the function at hand, it may take considerable time, resources, and many iterations, until the product arrives successfully to the market. From our 20+ years experience helping customers bring reliable products to the market, we at DSP ALGORITHMS understand the difficulties involved as no others. Our solution to such complex projects is to provide a plug-in programmable hardware card implementing the whole new function. With this solution, the design problem reduces to the need to understand how to interface to the card as a black box, just like any other semiconductor chip. The new function firmware is stored on the non-volatile memory on the OCEAN OEM CARD and protected from copying and tampering using the memory chip hardware IP protection features. Once powered, the processor loads the software from non-volatile flash memory and starts running the application in a fraction of a second.

The OCEAN-OEM-CARD (OCEAN-ADSP21489)

The OCEAN-OEM-CARD is an audio processing module without any audio converters or user interface. It is designed to plug into the application's main PCB. The OCEAN-OEM-CARD includes the audio processor, flash memory, and regulated power supply. All processor peripherals are brought out to a an industry standard header to interface to the application's main PCB. Depends on the required processing load, any Analog Devices SHARC DSP can be used as an audio processor, including the new 2156x. As an example, the specifications for the standard OCEAN-OEM-CARD are as follows: Dimensions 60mm x 41mm Processor Analog Devices ADSP21489, 400 MHz, 5 MBit internal memory, 32-bit/40-bit floating point and 32-bit fixed-point SIMD processor Flash Memory Winbond W25X40CL, 4MBit SPI flash memory with IP protection support. Power Supply Input Unregulated 5v DC through 2-pin 0.1" header or micro USB connector. All regulated supply voltages are generated on board. SPI Header 8-pin male 0.1" header for programming the flash memory and communicating with the processor (SPI commands). Interface Header 46-pin header.

The OCEAN-OEM-CARD Interface with Main PCB

The OCEAN-OEM-CARD communicates with the main application PCB through two communication channels. The first channel is the audio channel, and the second is the control channel. The main application PCB is responsible for managing audio sampling and interfacing to audio sources (microphones, incoming network audio channels, USB recording, etc) and audio sinks (loudspeakers, outgoing network audio channels, USB playback, etc). The main PCB sends audio samples that need to be processed to the OCEAN-OEM-CARD through the audio channel. The OCEAN-OEM-CARD processes the audio samples and sends them back to the main PCB. The audio channel communication is implemented using industry standard I2S or TDM protocol as needed. Besides the audio channel, the standard OCEAN-OEM-CARD firmware also supports a Serial Port Interface (SPI) control channel. Through this control channel, the main PCB can send commands to the OCEAN-OEM-CARD, for instance to enable or disable audio processing features, set audio processing parameters, or retrieve performance measures. For every command the OCEAN-OEM-CARD receives, it responds with the corresponding reply to that command, achieving a full control on audio processing.

Available firmware packages

• 8-element beamforming microphone array with Acoustic Echo Canceller (48kHz sampling rate, 250 ms echo tail length). Suitable for pro-audio conferencing applications in small to medium rooms.
• 8-element beamforming microphone array with Acoustic Echo Canceller and Acoustic Feedback Canceller (48kHz sampling rate, 250 ms echo tail length). Suitable for pro-audio conferencing applications in large conference rooms where sound reinforcement is needed.
• 8 to 16-element beamforming microphone array without echo cancellation (48kHz sampling rate). Suitable for speech recognition, dictation, voice commands, far-field recording, and studio quality recording.
• Adaptive Acoustic Feedback Cancellation with up to 8 microphones and 8 loudspeakers.
• 8-channels Adaptive Interference Canceller combined with BRIL Noise Reduction and beamforming at 48 kHz sampling rate. Suitable for use in communication devices in noisy acoustic environments such as race cars, motorbikes, and industrial environments.
• 4-rooms Acoustic Echo Canceller, each having its own separate reference and microphone (48kHz sampling rate, 250 ms echo tail length). Suitable for multi-party conferencing and server-side AEC processing.
• 4 channels combined Network Echo Canceller and Acoustic Echo Canceller, each having its own separate reference. Suitable for use with devices supporting multiple simultaneous calls.
• Multiple-channel combined Network Echo Canceller and Acoustic Echo Canceller, for use with PBX and gateways. Up to 32 channels, each of 128ms tail length at 8 KHz sampling rate can fit on a single OCEAN-ADSP21489 Card.
• Multiple-channel Network Echo Canceller for use with PBX and gateways. Up to 128 Network Echo Canceller channels, each of 32ms tail length at 8 KHz sampling rate can fit on a single OCEAN-ADSP21489 Card.
• Active Noise and Vibration Control with multiple references, multiple control sensors and multiple control actuators (2 references, 6 control sensors, and 8 control actuator standard).

The OCEAN-0808HC
The OCEAN-0808HC is a separate module designed to interface with the OCEAN-OEM-CARD for demonstration, testing, and evaluation purposes. It includes 8 analog inputs, 8 analog outputs, and simple manual user interface consisting in 4 buttons and 8 LEDs. The OCEAN-0808HC provides the audio channel interface to the OCEAN-OEM-CARD but no SPI control channel (manual user interface instead). To form a complete fully controllable system, the full control channel is provided by a separate Linux Single Board Computer (SBC). The SBC implements a web interface which receives commands from any device connected to a local network and translates those commands to SPI commands sent to the OCEAN-OEM-CARD. The OCEAN-0808HC specifications are as follows. Dimensions 60mm x 95mm Interface Header 46-pin female 0.1" right angle header. Analog Inputs 8 differential or single ended input channels brought out on 0.1" headers. Analog Outputs 8 single ended output channels brought out on 0.1" headers. Analog to Digital Converter 2x AK5703EN , 24-bit, 96 dB S/N, 100 dB Interchannel Isolation. Digital to Analog Converter 4x AK4420ET , 24-bit, 105 dB dynamic range, -92 dB THD+N, 100 dB Interchannel Isolation. User Interface 4 push-buttons and 8 LEDs.

Documents

• OCEAN-ADSP21489-0808HC hardware
• OCEAN-ADSP21489-0808HC conference firmware for small and medium rooms (no acoustic feedback canceller included)
• OCEAN-ADSP21489-0808HC conference firmware for large rooms with sound reinforcement (acoustic feedback canceller included).
• OCEAN-ADSP21489-0808HC Noise Management firmware .
• OCEAN-ADSP21489-1204HC hardware
• OCEAN-ADSP21489-1204HC conference firmware for small and medium rooms (no acoustic feedback canceller included)
• OCEAN-ADSP21489-1204HC conference firmware for large rooms with sound reinforcement (acoustic feedback canceller included).