DA-250 DSP Stereo Array Microphone Module Specification

Transcription

1 - Andrea Audio Test Labs DA-25 DSP Stereo Array Microphone Module Specification Dec 12 th 213 Rev D Andrea Electronics Corporation 65 Orville Drive Suite One Bohemia NY (631) This product is covered by Andrea Electronics Corporation s Patent No s: 5,673,325; 5,825,898; 6,49,67; 6,178,248; 6,332,28; 6,363,345; 6,377,637; 6,483,923; 6,594,367; 8,15,54 and Patents Pending - Proprietary Document - Andrea Electronics Page 1

2 DA-25 DSP Stereo Array Microphone Module Specification Audio IC; ADSP-BF592 DSP Processor (4MHz Max) 16 bit DAC and 16 bit ADC Interface and control: - Stereo Analog Signal Input from Stereo Microphones - Analog Signal Output to Audio Device - 1 Pin on Board Header for Microphone output, Power and Control - 4 Pin on Board Header for Microphone Input - One SPI Digital Port to Host Device (Optional) - One I2S Digital Audio Port - Microphone Mute Control from Microphone Mute Button DSP Processing Function - Noise reduction - Stereo Beam Forming (Up to 8ft) - Acoustic Echo Cancellation (AEC Optional) - Microphone AGC (Optional) - Digital Equalizer (Optional) LED Indicator: Power On/Off (Optional) Low power consumption, less than.2 Watts RoHS compliant Andrea Electronics Page 2

3 Audio Characteristics Parameter Limits Unit Condition Min Typ Max Gain 4 6 db Audio Frequency Response 4 12K Hz 4 8K Hz Battery Mode THD+N 2 % Microphone Input Level.1.1 Vrms Output Line Level 2.2 Vpp AEC Reference Input Level.1.1 Vrms S/(N+D) 85 db Line Output Dynamic Range 87 DBFs=S Noise Reduction1 8 db DSDA only Noise Reduction2 2 db DSDA + PureAudio Noise Reduction3 3 db DSDA + aggressive PureAudio AGC 2 db Optional Output Impedance 2 OHM Temperature Range degree Input Power VDC VDC Input Current ma *33mA for Battery Mode Andrea Electronics Page 3

4 Block Diagram Audio Device MIC Output AMP DAC CODEC Sereo Input Sereo Output ALC 2CH ADC F+ GND MIC_R Feed Back MIC_L MIC GND Input I2S MCLK 6.25M M I2C Control Digtal Audio Interface EXT-CLK I2S SPI1 25MHZ Crystal FLASH BF 592 DSP AEC SPI NC BF JTAG BUTTON: MIC MUTE LED: POWER ON LED Application Audio device Microphone Input for Hands Free Array Microphone for clear communications and enhanced far-field speech recognition accuracy Andrea Electronics Page 4

5 Dimension DISTANCE IS T.B.D. DRIVEN BY ANGLE OF ACCEPTED VOICE CONTROL AREA 7-11 PIN HEADER (T.B.D.) DEPENDING ON FUNCTIONAL INTERFACE.85 MICROPHONE HOLE SHAPE OPTIONAL. HOLE SIZE SHOULD BE.7 MIN AND CAN BE PART OF A GRILL PATTERN AS LONG AS THE MICROPHONE IS COMPLETELY SEALED TO THE EXTERIOR SURFACE OF THE DEVICE. SHIELDED MICROPHONE WIRE LENGTH T.B.D. DEPENDING ON PCB LOCATION 1.75 MICROPHONE CYLINDER PART OF HOUSING HOUSING 4mm MICROPHONES SHIELDED WIRES MOISTURE/DUST BARRIER TO PROTECT MICROPHONE MICROPHONE BOOT 3 DUROMETER RUBBER PRESS FIT INTO CYLINDER TO SECURE MICROPHONE DSP PCB Connector layout Part # AR J POWER(VDC) GND SHIELD MIC MUTE+ MIC MUTE- FEEDBACK+ FEEDBACK- MIC LEFT OUTPUT+ MIC RIGHT OUTPUT+ MIC GND J MIC LEFT INPUT- MIC LEFT INPUT+ MIC RIGHT INPUT+ MIC RIGHT INPUT- Andrea Electronics Page 5

6 Frequency Response 2 2 Gain (DB) KHz Sample Rate No Filters 24KHz Sample Rate DSDA/PA 16KHz Sample Rate DSDA/PA Frequency (Hz) Distortion Distortion (%) KHz Sample Rate Frequency (Hz) Andrea Electronics Page 6

7 Polar Plot Response The 36º plotted response is based on a 1KHz source tone placed at 18 distance from the DA-25 array microphone Board. Microphone 7. Spacing Polar Plot 1KHZ Omni 6" Distance Omni 3.5" Distance Uni 6" Distance Uni 3.5" Distance Andrea Electronics Page 7

8 Pure Audio (Noise Reduction) Test is conducted with White Noise directly injected into the DA-25 PC Board. The White noise signal contains equal power within a fixed bandwidth at all frequencies (2-2KHz). Microphones are by passed to accurately measure the PureAudio Filter performance. Noise Suppression = -15dB Initial Attack Time = >2mS White Noise = 15.67dB Reduction = 3.45dB >2mS Attack Time Pure Audio (Noise Reduction) per Frequency 2 4 Gain (db) White Noise White Noise Reduction (PureAudio) Frquency (Hz) 1 1 Andrea Electronics Page 8

9 Speech Recognition Accuracy Setup Testing was performed under the following controlled, but real life conditions: The setup used a computer as the source of the 1411kbps high quality speech file that is played from the PC through a Brüel & Kjær artificial head simulator. To ensure repeatable results the Speech files are combined into a single stereo file that is played though the head simulator calibrated at 92db SPL. The tests are preformed according to the specifications of the Nuance Dragon test procedure. All text readings transcribed by Dragon Naturally speaking 12.5 Software were rated with a scoring utility application that checks for word recognition efficiency. The scores can be used to determine the amount of distortion in Microphone recordings. The DA25 Array Microphone is placed in a fixed position at 18 Distance from the B&K Head Simulator. A generated Speech wave file text reading is played through the B&K Head Simulator. The Speech output is calibrated and adjusted for 92 db SPL max at 1 distance away from Mouth Simulator. The DA25 array microphone is subjected to speech-training prior to testing. Each microphone has a specific user setting with Dragon NaturallySpeaking 12.5 to compensate for gain and noise variance. Pink noise played from loud speakers is used to simulate the environmental noise and is calibrated at 65dB SPL measured from the device being tested. Andrea s PureAudio & Beam Forming filters are enabled during speech recognition testing. Loud Speaker Loud Speaker 9º B & K Type 442 Head Simulator 18 DA-25 Loud Speaker Loud Speaker DA25 Speech Recognition Accuracy Data 24KHz Sample Rate Microphone Omni Directional Uni Directional Omni Directional Uni Directional Microphone Spacing 6" 3.5" 3.5" 6" No Noise 95.98% 95.98% 95.98% 95.98% 72dB SPL Environmental Noise 94.3% 93.13% 62.63% 92.42% This speech recognition data is for reference only and does not represent potential optimum accuracy. Andrea Electronics Page 9