Digital Voice Systems VC-20-MR2 User Manual Download Page 1

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The Speech Compression Specialists

IGITAL

OICE

YSTEMS

Voted To be
The BEST…

…10100110101110101001

…101111010100110101

2.2

2.4

2.6

2.8

3.2

3.4

3.6

3.8

4.2

Clean (MOS)

Traffic

(DMOS)

Truck Noise

@ 15dB

Truck Noise

@ 6dB

Babble

(DMOS)

Background Noise Condition

AMBE Voice Coder @ 3.6 kbs
Avg. of Others @ 3.6 bps
VSELP @ 8.0 kbps

Mean Opinion
Score

(MOS or DMOS)

Best

Vocoder

Summary of Contents for VC-20-MR2

Page 1: ... 101111010100110101 2 2 2 2 4 2 6 2 8 3 3 2 3 4 3 6 3 8 4 4 2 C lean M O S Traffic D M O S TruckNoise 1 5 d B TruckN o ise 6 d B Babble D M O S BackgroundNoiseCondition A M B EVoiceCoder 3 6kbs A v g ofO thers 3 6bps V S E L P 8 0kbps M eanOpinion Score M O S orD M O S F I R S T P L A C E B est Vocoder ...

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Page 3: ...VC 20 AMBE Vocoder Board User s Manual The Speech Compression Specialists DIGITAL VOICE SYSTEMS INC VC 20 AMBE Vocoder Board USERS MANUAL Version 2 0 ...

Page 4: ... 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 Digital Voice Systems Inc shall not be liable for any errors or for incidental or consequential damages in connection with the furnishing performance or use of this manual or the examples herein The information in this...

Page 5: ...together with a copy of this Agreement provided that END USER provides DVSI with a written notification of the transfer and provided that the third party agrees in writing to accept all the terms and conditions of this agreement Upon any such transfer END USER s rights under this Agreement shall terminate pursuant to Section 3 0 b END USER may relocate the Voice Codec and the subsequent location s...

Page 6: ... USER specific legal rights and END USER may have other rights which vary from state to state 8 0 Limitation of Liability 8 1 In no event shall DVSI be liable for any special incidental indirect or consequential damages resulting from the use or performance of the Voice Codec or VC 20 AMBE Vocoder Board whether based on an action in contract tort including negligence or otherwise including without...

Page 7: ...BE VOCODER BOARD OVERVIEW 5 2 1 ADVANCED MULTI BAND EXCITATION AMBE VOCODER 5 2 2 VC 20 AMBE VOCODER BOARD BASIC OPERATION 5 2 3 SPECIAL HANDLING AND STORAGE PRECAUTIONS 7 Section 33 BOARD SET UP CONFIGURATION 9 3 1 CONNECTION SPECIFICATIONS 9 3 2 DIN41612 96 PIN CONNECTOR SPECIFICATIONS 10 3 3 VC 20 MR2 CONNECTOR SIGNALS 11 3 4 VC 20 MR2 CONNECTOR SIGNALS 11 3 5 VC 20 MR2 ON BOARD JUMPERS CONNECT...

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Page 9: ...4 8 2 4 kbps data bit stream from a modem or similar device This received bit stream is processed by the decoder and converted into a synthetic speech signal which is then converted into an analog signal using the on board D to A converter The encoder and decoder are fully asynchronous The VC 20 MR2 4800bps has been designed to be robust to both acoustic background noise and channel errors It gene...

Page 10: ...ovide performance equal to today s digital cellular systems at under half the data rate The AMBE voice compression algorithm is used in applications throughout the world including the next generation of digital mobile communication systems 1 2 VC 20 AMBE Vocoder Board Features High Quality Low Data Rate Speech Coding Extremely Flexible Bit Rate Selection 1 3 AMBE 1000 Vocoder Chip Features High Qu...

Page 11: ...ard User s Manual page 3 The Speech Compression Specialists DIGITAL VOICE SYSTEMS INC Cellular Telephony and PCS Satellite Communications Digital Mobile Radio Secure Communications Voice Multiplexing Voice Mail Multimedia Applications Video Conferencing ...

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Page 13: ...ther CELP or VSELP and therefore it is easily integrated into low cost low power communication integrated circuits 2 2 VC 20 AMBE Vocoder Board Basic Operation 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 ...

Page 14: ...ng their on board clocks to generate the signals TXCK FMEN RXCK and FMDE In this mode the encoder on the first VC 20 MR2 is connected to the decoder on the second VC 20 MR2 Similarly the decoder on the first VC 20 MR2 is connected to the encoder on the second VC 20 MR2 This is shown in Figure 4 Generally the encoder signals on each board are synchronized with the oscillator on that board and the d...

Page 15: ...olding the RATE high selects the 4 8kbs system holding it low selects the 2 4kps system 2 3 Special Handling and Storage Precautions CAUTION Handling Instructions Although the VC 20 AMBE Vocoder Board incorporates input protection circuitry to avoid damage from the accumulation of a static charge industry standard electrostatic discharge precautions and procedures must be employed during handling ...

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Page 17: ...ance 600 ohm Sensitivity 0 dBm0 0 dBm Sinusoidal Overload 3 17 dBm0 Nominal Level 23 dBm0 average speech level Dynamic Range 10 dB relative to Nominal Level Noise Level 72 dBm0 Analog Output Type single ended Impedance low impedance output capable of driving a 600 ohm load Sensitivity 0 dBm0 0 dBm Sinusoidal Overload 3 17 dBm0 Nominal Level 23 dBm0 average speech level Dynamic Range 10 dB relative...

Page 18: ...d 15 Output DTMF_DET Rsvd Input DINRS 16 Output DTMF_DAT Rsvd Rsvd 17 Output ENSLNCE Rsvd Rsvd 18 Input RXD1 Rsvd Rsvd 19 Input RXD0 Rsvd Rsvd RATE 20 Gnd GND Rsvd Gnd GND 21 Input LOST Rsvd Rsvd 22 Rsvd Rsvd Input FS 23 Rsvd Rsvd Input ECHO 24 Input VAD Rsvd Rsvd 25 Input DESLNCE Rsvd Rsvd 26 Gnd GND Rsvd Gnd GND 27 Anlg Pwr 5v analog Rsvd Anlg Pwr 5v analog 28 Anlg Pwr 5v analog Rsvd Anlg Pwr 5v...

Page 19: ...der frame flag Active High FS I Frame Steal Flag Active Low GND Pwr Digital Ground GND Anlg Pwr Analog Ground HD_SD I Enable Soft decision Decoding Active Low LOST I Lost speech frame detected flag Active High RATE I Rate selection pin High 4 8bps Low 2 4bps RESX O Internal Reset Status Active Low RUN O Run Status Signal Active High RXCK I Receive data bit clock 4 8 2 4 kHz RXD I Receive data I ch...

Page 20: ... DTMF_DET is high The data is synchronous with the rising edge of TXCK This signal should be ignored when DTMF_DET is inactive DTMF_DET The DTMF_DET flag is activated by the encoder if it detects a dtmf tone on VRXI The DTMF_DET is brought high on a rising edge of TXCK and held high for four clock cycles During this time the DTMF data is output on DTMF_DAT The DTMF_DET flag is only output once for...

Page 21: ...frame steal packet on TXD If left unconnected this signal is pulled internally to the disabled state 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 This signal is sampled on the falling edge of the f...

Page 22: ...nals input to the decoder These signals provide three bits of soft decision information with RXD being the MSB and RXD0 being the LSB These signals are each clocked into the VC 20 MR2 on each falling edge of RXCK resulting in a total data rate of 4 8 2 4 kbps Note that when interfacing to a modem or other device that only provides a single bit of received data i e hard decision then this signal sh...

Page 23: ...ects TXD to RXD MSB 8 reserved leave unconnected 9 reserved leave unconnected 10 reserved leave unconnected 11 Deactivates LOST signal 12 Connects ENSLNCE to DESLNCE signal 13 reserved leave unconnected 14 reserved leave unconnected 3 6 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...

Page 24: ... 4 1209 Hz 770 Hz 0010 7 1209 Hz 852 Hz 0011 1209 Hz 941 Hz 0100 2 1336 Hz 697 Hz 0101 5 1336 Hz 770 Hz 0110 8 1336 Hz 852 Hz 0111 0 1336 Hz 941 Hz 1000 3 1477 Hz 697 Hz 1001 6 1477 Hz 770 Hz 1010 9 1477 Hz 852 Hz 1011 1477 Hz 941 Hz 1100 A 1633 Hz 697 Hz 1101 B 1633 Hz 770 Hz 1110 C 1633 Hz 852 Hz 1111 D 1633 Hz 941 Hz Table 1 DTMF Tone Data By default the VC 20 AMBE is jumpered to use IRQ 11 and...

Page 25: ... VOICE SYSTEMS INC 4 DVSI Services and Support Solutions 4 1 Technical Support If you have any problems with the VC 20 AMBE or have questions about its operation please contact Digital Voice Systems Inc 234 Littleton Road Westford MA 01886 USA Phone 978 392 0002 Fax 978 392 880166 email info dvsinc com web www dvsinc com ...

Page 26: ...E DESLNCE RXD RXD1 RXD0 RXCK LOST ENCODER DECODER Figure 2 Vocoder Connections In Loop back Mode On Board Clock Frame Generator VFXI VFRO jumper 1 jumper 3 jumpers 5 6 7 jumper 12 jumper 4 jumper 2 jumper 11 HD_SD ECHO VAD RATE ...

Page 27: ... Speech Compression Specialists DIGITAL VOICE SYSTEMS INC TXD TXCK FMEN FMDE DESLNCE RXD RXD1 RXD0 RXCK LOST ENCODER DECODER MODEM Figure 3 Typical Connections between Vocoder and a General Modem VFXI VFRO HD_SD ECHO VAD RATE ENSLNCE Note Not meant to represent an off the shelf modem ...

Page 28: ...ER 1 DECODER 1 On Board Clock Frame Generator 1 FMEN TXCK LOST FMEN TXCK FMDE RXCK TXD DESLNCE TXD RXD On Board Clock Frame Generator 2 VFXI VFRO VFRO VFXI jumper 11 jumper 3 jumper 1 jumper 3 jumper 11 jumper 1 jumper 12 jumper 12 HD_SD ECHO VAD RATE HD_SD ECHO VAD RATE ENSLNCE ENSLNCE ...

Page 29: ...r s Manual page 21 The Speech Compression Specialists DIGITAL VOICE SYSTEMS INC Figure 5 Channel Interface Timing Relationships TXCK FMEN TXD ENSLNCE 500 ns RXCK FMDE RXD RXD1 RXD0 LOST DESLNCE HD_SD VAD ECHO 500 ns 20 ms 1 rate seconds 20 ms N A 1 rate seconds ...

Page 30: ...RUN 13 25ms 20ms Figure 6 RUN Signal Timing 6 75ms Encoder Window Decoder Window ...

Page 31: ...oard User s Manual page 23 The Speech Compression Specialists DIGITAL VOICE SYSTEMS INC Figure 7 Vocoder Physical Dimensions bottom view 3 0 mm 5 5 mm 41612 Connector 112 mm 100 mm 7 5 mm side view 11 mm 7 5 mm 112 mm components 12 5 mm connections 2 mm ...

Page 32: ...NOTES ...

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