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D
V
IGITAL
The Speech Compression Specialists
...10100110101110101001
Voted To be
The BEST...
S
OICE
YSTEMS
M ean Opinion
Score
( M O S or D M O S)
B est
Vocoder
F
P
I
L
A
R
S
T
, I
.
NC
4.2
4
3.8
3.6
3.4
3.2
C
3
E
2.8
2.6
2.4
2.2
2
C lean (M O S )
Traffic
(D M O S )
Background Noise Condition
...101111010100110101
A M B E Voice Coder @ 3.6 kbs
A v g . of O thers @ 3.6 bps
V S E L P @ 8.0 kbps
Truck Noise
Truck N o ise
@ 1 5 d B
@ 6 d B
Babble
( D M O S )
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Related Manuals for Digital Voice Systems VC-20-MR2
Summary of Contents for Digital Voice Systems VC-20-MR2
- Page 1 IGITAL OICE The Speech Compression Specialists …10100110101110101001 Voted To be The BEST… YSTEMS M ean Opinion Score ( M O S or D M O S) B est Vocoder C lean (M O S ) Background Noise Condition …101111010100110101 A M B E Voice Coder @ 3.6 kbs A v g .
- Page 3 IGITAL OICE YSTEMS The Speech Compression Specialists VC-20 AMBE Vocoder Board USERS MANUAL Version 2.0 VC-20 AMBE™ Vocoder Board User’s Manual...
- Page 4 Digital Voice Systems, Incorporated. Every effort has been made to ensure the accuracy of this manual. However, Digital Voice Systems, Inc. makes no warranties with respect to the documentation and disclaims any implied warranties of merchantability and fitness for a particular purpose.
- Page 5 END USER has requested a license, and any derivative works thereof, including modifications, enhancements and extensions made by or for Digital Voice Systems, Inc. (DVSI) and including circuit diagrams, timing diagrams, programmable logic software, logic diagrams, layouts, operating instructions and user manuals.
- Page 6 Agreement shall remain in full force and effect. 12.0 Notices 12.1 Any notices to DVSI which may be given hereunder shall be in writing and sent to: Digital Voice Systems Inc., 234 Littleton Road, Westford, MA., 01886, U.S.A. VC-20 AMBE™ Vocoder Board User’s Manual...
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Page 7: Table Of Contents
Section 2 DVANCED VC-20 AMBE PECIAL Section 3 OARD ONNECTION DIN41612 96- VC-20-MR2 C VC-20-MR2 C VC-20-MR2 VC-20-MR2 DTMF T DVSI S Section 4 ERVICES AND ECHNICAL VC-20 AMBE™ Vocoder Board User’s Manual ABLE OF ONTENTS ... 1 ... 1 NFORMATION... -
Page 9: Ntroduction
The Speech Compression Specialists Product Introduction General Information The Digital Voice Systems, Inc. (DVSI) VC-20-MR2 voice codec is a full-duplex real-time voice processing board. The VC-20-MR2 contains proprietary software which implements the Advanced Multi-Band Excitation (AMBE™) voice coding algorithm. DVSI grants a license to its customers to use this software according to the terms established in the attached AMBE™... -
Page 10: Ambe
DVSI Full Duplex AMBE Voice Coder Supports Data Rates of 2.4 kbps and 4.8 kbps Self-Test Loop-Back Mode Echo Cancellation Dual Tone / DTMF Power-Down Mode AMBE™ Vocoder Applications: page 2 IGITAL OICE YSTEMS, The Speech Compression Specialists VC-20 AMBE™ Vocoder Board User’s Manual... - Page 11 IGITAL OICE YSTEMS, The Speech Compression Specialists Cellular Telephony and PCS Satellite Communications Digital Mobile Radio Secure Communications Voice Multiplexing Voice Mail Multimedia Applications Video Conferencing VC-20 AMBE™ Vocoder Board User’s Manual Section 1- Product Introduction page 3...
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Page 13: Overview
Connections are made to the VC-20-MR2 using the attached DIN 41612 connector which is described in Sections 4 and 5. The user must supply the VC-20-MR2 with a 5v digital power supply and a +/-5v analog power supply. It is preferable to decouple the analog supply from the digital supply by using separate power supplies. - Page 14 Section 2 - VC-20 AMBE™ Vocoder Board Overview The VC-20-MR2 can be connected to a modem or similar device as shown in Figure 3. The modem or the VC-20-MR2 can generate the clocks (TXCK and RXCK) and frame synchronization (FMEN and FMDE). The modem reads the data from the encoder on the data line TXD.
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Page 15: Handling Instructions
Note that for proper operation any background noise present in the speech must be short term stationary and have a level less than -25 dBm0. The RATE signal controls which version the VC-20-MR2 voice codec runs. Holding the RATE high selects the 4.8kbs. system , holding it low selects the 2.4kps. -
Page 17: Up & Configuration
Nominal Level Dynamic Range Noise Level Bandwidth Digital Interface: Type TTL compatible Power: VC-20 AMBE™ Vocoder Board User’s Manual single-ended 600 ohm 0 dBm0 = 0 dBm +3.17 dBm0 -23 dBm0 (average speech level) +/- 10 dB (relative to Nominal Level) -
Page 18: Din41612 96-Pin Connector Specifications
INPwr.UT to the VC-20-MR2 OUTPwr.UT from the VC-20-MR2 RESERVED (Leave Unconnected) Note: Many Reserved signals are used to monitor the internal state of the VC-20-MR2. To ensure proper operation all reserved signals must be left unconnected. page 10 ROW B... -
Page 19: Vc-20-Mr2 Connector Signals
IGITAL OICE YSTEMS, The Speech Compression Specialists VC-20-MR2 Connector Signals Name DESLNCE DINRS DTMF_DAT DTMF_DET ECHO ENSLNCE FMDE FMEN GND Anlg HD_SD LOST RATE RESX RXCK RXD0 RXD1 TXCK VFRO VRXI VC-20-MR2 Connector Signals VC-20 AMBE™ Vocoder Board User’s Manual Description Pwr. - Page 20 DESLNCE is low. DINRS DINRS is a VC-20-MR2 reset signal. An active high level on DINRS for a duration of at least 300 ns will reset the VC-20-MR2. DINRS will generate RESX and RESET.
- Page 21 (high). GND, AGND GND is the digital ground signal and AGND is the analog ground signal. These signals are connected on the VC-20-MR2. HD_SD The HD_SD signal must be set low to enable soft-decision decoding or held high to disable soft decision decoding.
- Page 22 Section 6 – Advanced Features RESX RESX is the reset status output signal. It is active when the VC-20-MR2 is being reset. The VC-20-MR2 is reset under three conditions: during power-up, as a result of DINRS being asserted, or as a result of a Watch-Dog Timer reset. This signal is an active low output.
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Page 23: Connector Signals
VC-20-MR2 on-board jumpers Connector Signals Jumper VC-20-MR2 DTMF Tone Data The VC-20-MR2 supports dtmf detection, transmission, and generation. The encoder detects and transmits dtmf tones, and the decoder decodes and generates dtmf tones, in support of standard telephony requirements In addition, if the VC-20 encoder detects a dtmf tone it activates the DTMF_DET signal for four clock cycles of TXCK and simultaneously outputs (LSB first) four bits of data on DTMF_DAT which identify the dtmf tone which was detected. -
Page 24: Features
The Speech Compression Specialists Frequency 697 Hz. 770 Hz. 852 Hz. 941 Hz. 697 Hz. 770 Hz. 852 Hz. 941 Hz. 697 Hz. 770 Hz. 852 Hz. 941 Hz. 697 Hz. 770 Hz. 852 Hz. 941 Hz. VC-20 AMBE™ Vocoder Board User’s Manual... -
Page 25: Ervices And Support Sechnical Support
If you have any problems with the VC-20 AMBE™ or have questions about its operation, please contact: VC-20 AMBE™ Vocoder Board User’s Manual Section 7- DVSI Services & Support Digital Voice Systems, Inc. 234 Littleton Road Westford, MA 01886 USA Phone: (978) 392-0002... - Page 26 TXCK (jumper 1) FMEN (jumper 3) ENSLNCE (jumper 12) (jumpers 5,6,7) HD_SD, ECHO, VAD, RATE RXD, RXD1, RXD0 DESLNCE FMDE (jumper 4) RXCK (jumper 2) LOST (jumper 11) Figure 2: Vocoder Connections In Loop-back Mode On-Board Clock & Frame Generator VFXI ENCODER DECODER...
- Page 27 The Speech Compression Specialists HD_SD, ECHO, VAD, RATE MODEM Figure 3: Typical Connections between Vocoder and a General Modem Note: Not meant to represent an “off-the-shelf” modem VC-20 AMBE™ Vocoder Board User’s Manual TXCK FMEN ENCODER ENS LNCE RXD, RXD1, RXD0...
- Page 28 DECODER VFRO ENCODER VFXI On-Board Clock & Frame Generator Figure 4: Dual Vocoder Connections (jumper 1) (jumper 3) LOST (jumper 11) RXCK TXCK FMDE FMEN DESLNCE ENSLNCE (jumper 12) HD_SD, ECHO, VAD, RATE HD_SD, ECHO, VAD, RATE ENSLNCE DESLNCE (jumper 12) FMEN FMDE TXCK...
- Page 29 500 ns RXCK FMDE RXD, RXD1, RXD0 LOST, DESLNCE, HD_SD, VAD, ECHO Figure 5: Channel Interface Timing Relationships VC-20 AMBE™ Vocoder Board User’s Manual Section 7- DVSI Services & Support 1/rate (seconds) 20 ms 1/rate (seconds) 20 ms page 21...
- Page 30 Figure 6: RUN Signal Timing 20ms 13.25ms Encoder Window 6.75ms Decoder Window...
- Page 31 The Speech Compression Specialists 5.5 mm 3.0 mm 11 mm < 7.5 mm Figure 7: Vocoder Physical Dimensions VC-20 AMBE™ Vocoder Board User’s Manual 41612 Connector 100 mm (bottom view) 112 mm (components < 12.5 mm) (connections < 2 mm) (side view) Section 7- DVSI Services &...
- Page 32 NOTES...
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