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Digital Voice Systems AMBE-2000 User Manual

Vocoder chip
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Digital Voice Systems, Inc.
The Speech Compression Specialists
AMBE-2000™ Vocoder Chip
User's Manual
Version 4.92 June, 08

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  • Page 1 Digital Voice Systems, Inc. The Speech Compression Specialists AMBE-2000™ Vocoder Chip User’s Manual Version 4.92 June, 08...
  • Page 2 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. This includes business interruption and/or other loss which may arise from the use of this product.
  • Page 3 1. Preliminary Statements and Definitions 1.1 This nonexclusive end user product license agreement is a legal agreement between the customer (the END USER) and Digital Voice Systems, Inc. (DVSI) covering the terms and conditions under which DVSI's proprietary content (that may consist of and is not limited to software, hardware, documentation and other material) is licensed to the END USER as part of this PRODUCT.
  • Page 4 DVSI Confidential Proprietary, Subject to Change Visit us at www.dvsinc.com AMBE-2000™ Vocoder Chip Users Manual Version 4.92, June, 08 limited to, all sales, use, rental receipt, personal property or other taxes which may be levied or assessed in connection with this Agreement.

  • Page 5: Table Of Contents

    1. Product Introduction General Information Advantages Typical Applications 2. AMBE-2000™ Application Design Overview Basic Operation Initial Design Considerations 2.2.1 A/D – D/A Overview 2.2.2 Vocoder Front End Requirements 2.2.3 Channel Interface Overview 2.2.4 Speech and FEC Rate Selection Overview Hardware Information Special Handling Instructions 3.1.1...
  • Page 6 Interfacing to the Texas Instruments PCM3500 Codec Expanded Tone Detection and Generation Soft Decision Decoding Special Rate 2350 bps Voice / 50 bps FEC AMBE-1000™ Vocoder Chip Compatible Mode 64 DVSI Confidential Proprietary, Subject to Change Visit us at www.dvsinc.com AMBE-2000™...

  • Page 7: Product Introduction

    Typically for higher error rate channels, the user will apportion a greater percentage of the total bit rate to FEC coding. The AMBE-2000™ voice coder maintains natural voice quality and speech intelligibility at rates as low as 2.0 kbits/sec. The ...

  • Page 8: Typical Applications

    1.3 Typical Applications Satellite Communications Digital Mobile Radio Secure Communications Cellular Telephony and PCS Voice Multiplexing Voice Mail Multimedia Applications DVSI Confidential Proprietary, Subject to Change Visit us at www.dvsinc.com AMBE-2000™ Vocoder Chip Users Manual Version 4.92, June, 08 Page 8...

  • Page 9: A/D – D/A Overview

    2.1 Basic Operation In its simplest model, the AMBE-2000™ can be viewed as two separate components, the Encoder and the Decoder. The Encoder receives an 8kHz sampled stream of speech data (16-bit linear, 8-bit Alaw, or 8-bit ulaw) and outputs a stream of channel data at the desired rate.
  • Page 10 DVSI Confidential Proprietary, Subject to Change Visit us at www.dvsinc.com AMBE-2000™ Vocoder Chip Users Manual Version 4.92, June, 08 Vocoder Front End Analog...

  • Page 11: Channel Interface Overview

    The serial port can run in passive or active modes. In passive mode, all of the channel interface control signals are inputs to the AMBE-2000™ chip. In active mode, only the TX_DATA_STRB is an output from the AMBE-2000™...

  • Page 12: Speech And Fec Rate Selection Overview

    Chip to run in Passive or Active modes. In Passive mode, data strobes are provided by an external source, while in Active mode, data strobes are provided by the AMBE-2000™ Vocoder Chip. The serial interfaces can be run in Passive or Active modes.

  • Page 13: Special Handling Instructions

    The 100 pin TQFP package design of the AMBE-2000™ Vocoder Chip allows it to be mounted by infrared reflow, vapor- phase reflow or equivalent processes. The peak package body temperature must not exceed 220 C.

  • Page 14: Pin Descriptions

    Input should be unconnected. Input AMBE-2000™ Reset pin. Active LOW. See Section 3.3 Encode Packet Ready: Following a reset, this signal will have a high to low transition to Output indicate the first packet is ready. The next packet will be ready approximately 20 msec later.
  • Page 15 62,66,91,92 93,94,95,96 97,98,99 NOTE 1: The AMBE-2000™ expects an encoder packet to be read approximately every 20 msec. Following the initial reset, wait for EPR to go low and read the initial packet (t following packets use the procedure below: 1) Wait for slightly less than 20 msec.

  • Page 16: Clock And Reset Timing

    Clock and Reset Timing To reset the AMBE-2000 chip, the reset signal must be held low for a minimum of 50 µs. The recovery time from reset is approximately 95 ms. In other words, 95 ms after the rising edge of the reset signal the AMBE-2000™ starts processing PCM samples.
  • Page 17 CLKOUT is shown for reference only. It should not be connected in the circuit. DVSI Confidential Proprietary, Subject to Change Visit us at www.dvsinc.com AMBE-2000™ Vocoder Chip Users Manual Version 4.92, June, 08 Parameter Integer PLL multiplier N (N=4) (CI)/4...

  • Page 18: Crystal / Oscillator Usage

    * 1ms of idle time between encode and decode sequence. Crystal / Oscillator Usage The AMBE-2000™ Vocoder Chip has an input clock frequency of 16.384 MHz. Two options are outlined below in providing this signal. The CLOCK_MODE pin 51 must be set appropriately for the option used.
  • Page 19 Figure 3-D X2/CLKIN and X1 with Crystal Oscillator DVSI Confidential Proprietary, Subject to Change Visit us at www.dvsinc.com AMBE-2000™ Vocoder Chip Users Manual Version 4.92, June, 08 C1 = 10 pF X2/CLKIN (pin 68) 16.384 MHz X1 (pin 67) C2 = 10 pF...

  • Page 20: Package Description

    Package Description 100 pin TQFP (Thin Quad Flat Pack) All Dimensions are in millimeters Figure 3-E Package Dimensions Figure 3-F AMBE-2000 Chip Markings DVSI Confidential Proprietary, Subject to Change Visit us at www.dvsinc.com AMBE-2000™ Vocoder Chip Users Manual Version 4.92, June, 08 16.20 / 15.80 SQ...

  • Page 21: Normal Operating Conditions

    AMBE-2000-10 = The DVSI device part number. DVSI = Digital Voice Systems, Incorporated D16876PZ-66 = Internal Texas Instruments part number for the AMBE-2000 = WF Code = Die Rev Code = Die Shrink Code 43AT3FW = Lot Trace Code = 2 Digit YR/MO Code (Updated Monthly)

  • Page 22: Electrical Characteristics And Requirements

    Thermal Resistance Characteristics ΘJA ΘJC Table 3G Thermal Resistance Characteristics DVSI Confidential Proprietary, Subject to Change Visit us at www.dvsinc.com AMBE-2000™ Vocoder Chip Users Manual Version 4.92, June, 08 Absolute Maximum Ratings Parameter Test Conditions = 3.3 ±V, I = MAX...

  • Page 23: Channel Interface

    It is important to realize that not all data being output from the AMBE-2000™ is intended for transmission over the channel. Status type of data is typically only useful at the ‘local’ end. In most voice transmission systems, the actual encoded bits are extracted from the channel formatting, combined into the systems transmission stream, sent over the transmission path, extracted from the transmission path at the receiving end, and reassembled into the AMBE-2000™’s channel format for...

  • Page 24: Serial Configuration Selection

    1 to 4 voice data bits carried within each word. These four configurations can be seen in Table 4-B. See section 4.3 for all the details on the serial interface. DVSI Confidential Proprietary, Subject to Change Visit us at www.dvsinc.com AMBE-2000™ Vocoder Chip Users Manual Version 4.92, June, 08 Interface Select Pins Port Type...

  • Page 25: Channel Serial Mode

    The signals in Table 4-C make up the serial channel interface. The serial channel mode transfers data in and out of the AMBE-2000™ using 16 bit words on the two data lines CHAN_RX_DATA and CHAN_TX_DATA. The selection of the framed or unframed format of this data is made using information in Table 4-A.

  • Page 26: Low Level Timing For Passive And Active Serial Mode

    Hold time, FSR after CLKR falling edge h(FSR) Hold time, DR after CLKR falling edge h(DR) DVSI Confidential Proprietary, Subject to Change Visit us at www.dvsinc.com AMBE-2000™ Vocoder Chip Users Manual Version 4.92, June, 08 c(SCK) w(SCK) w(SCK) su(DR) h(DR)
  • Page 27 Note: H = 7.629 ns; however, do not operate serial clocks any faster than 2.048 MHz. Thus t minimum of 488.3 nsec. DVSI Confidential Proprietary, Subject to Change Visit us at www.dvsinc.com AMBE-2000™ Vocoder Chip Users Manual Version 4.92, June, 08 3.3 Volts Units 2H-5...

  • Page 28: Channel Data Format

    Otherwise, when the data rate is less than 9600bps, the coded voice bits are filled starting from the MSB of the first word in the field, leaving any unused bits as zeros. It is important to note here that even when the AMBE-2000™ is operating at less than 9600bps, all 384 bits of the Framed format (including any unused trailing zeros) must be transferred out of the encoder and into the decoder.

  • Page 29: Framed Input: Words 2-6 : Rate Information

    Rate Info 0, Rate Info 1, Rate Info 2, Rate Info 3, Rate Info 4 The initial rate of the AMBE-2000™ is set through the hardware pins RATE_SEL [4-0] (see Section 7.2 and Tables 7-A and 7- B). After resetting the device, the coding rate can be modified for both the encoder and the decoder by sending a framed packet to the input channel interface.

  • Page 30: Framed Input: Word 7 : Unused In Input

    0xbf9b 0x0080 0x0000 0xab5d 0x3400 0x0000 0xbfc0 0x0000 0x0000 0xab16 0xe400 0x0000 Table 5-D Rate Selection Using Rate Info 0-4, AMBE-2000™ only (AMBE+™) Rate Info 0 Rate Info 1 Rate Info 2 0x0028 0x0000 0x0000 0x5048 0x0000 0x0000 0x1030 0x0001...
  • Page 31 The DTMF Amplitude runs from 3 to –60 dBm0. This value is a signed byte (example: 0x03 = 3, 0x00 = 0, 0xC4 = -60). DVSI Confidential Proprietary, Subject to Change Visit us at www.dvsinc.com AMBE-2000™ Vocoder Chip Users Manual Version 4.92, June, 08 DTMF Control – 16-bits Frequency 1...

  • Page 32: Framed Input: Words 12-23 : Channel Data

    As is noted in the Channel Interface definitions, these unused bits must still be clocked out of the AMBE-2000™. The packet must always consist of 24 words.

  • Page 33: Framed Output: Word 1 : Power Control Id

    Decoder Frame Repeat: When the Decoder Frame Repeat flag is set to 1, the decoder is reporting that the last frame decoded was a repeat of the previous frame. DVSI Confidential Proprietary, Subject to Change Visit us at www.dvsinc.com AMBE-2000™ Vocoder Chip Users Manual Version 4.92, June, 08 Figure 5-B Basic Framed Output Description Header always set to 0x13ec Power Control ID (8bits) Control Word 1 (8 bits) –...

  • Page 34: Framed Output: Word 8 : Soft Decision Distance

    Rate Info 0, Rate Info 1, Rate Info 2, Rate Info 3, Rate Info 4. Words 2-6 in the packet indicate the rate at which the AMBE-2000™ encoder is operating. These words are output. See tables 5-C and 5-D for corresponding values.

  • Page 35: Framed Output: Word 10 : Dtmf Control

    DTMF Amplitude DVSI Confidential Proprietary, Subject to Change Visit us at www.dvsinc.com AMBE-2000™ Vocoder Chip Users Manual Version 4.92, June, 08 Description An input signal shall not be rejected as a DTMF tone if its amplitude is greater than -25 dBm0 (maximum sinusoid dBm0 is defined as+3.17 dBm0).

  • Page 36: Framed Output: Word 11 : Control Word 2

    Echo Canceller (EC): A 1 in this output field indicates that the echo canceller has been enabled. DVSI Confidential Proprietary, Subject to Change Visit us at www.dvsinc.com AMBE-2000™ Vocoder Chip Users Manual Version 4.92, June, 08 DTMF Digit Frequency 1 (Hz)

  • Page 37: Framed Output: Words 12-23 : Channel Data

    As is noted in the Channel Interface definitions, these unused bits must still be clocked out of the AMBE-2000™. The packet must always consist of 24 words.
  • Page 38 2 bits per Word Format 3 bits per Word Format 4 bits per Word Format DVSI Confidential Proprietary, Subject to Change Visit us at www.dvsinc.com AMBE-2000™ Vocoder Chip Users Manual Version 4.92, June, 08 Data Control Offset Control Data Page 38...

  • Page 39: Configuring The A/D-D/A Interface Using Codec_Sel [1-0]

    (20-4000Hz) the better the overall system will sound. The AMBE-2000™ Vocoder Chip operates with a speech data sample rate of 8kHz for both the A/D and D/A interfaces. This 8kHz data is input and output using a serial port on the AMBE-2000™.

  • Page 40: Low Level A/D–D/A Timing

    Hold time, FSR after CLKR falling edge h(FSR) Hold time, DR after CLKR falling edge h(DR) DVSI Confidential Proprietary, Subject to Change Visit us at www.dvsinc.com AMBE-2000™ Vocoder Chip Users Manual Version 4.92, June, 08 c(SCK) w(SCK) h(FSR) w(SCK) su(FSR)
  • Page 41 Note: H = 7.629 ns; however, do not operate serial clocks any faster than 2.048 MHz. Thus t minimum of 488.3 nsec. DVSI Confidential Proprietary, Subject to Change Visit us at www.dvsinc.com AMBE-2000™ Vocoder Chip Users Manual Version 4.92, June, 08 3.3 Volts Units 2H-5...

  • Page 42: Hardware Vs. Software Selection Note

    Coding Rate Selection The Voice coding rate as well as the FEC coding rate can be selected individually on the AMBE-2000™. These rates are selected by using the Rate Info Words as described in section 5.2.4, or through hardware pins RATE_SEL [4-0] subject to the restrictions in section 7.1.

  • Page 43: Echo Cancellation

    Echo Cancellation The AMBE-2000™ Vocoder Chip provides a 16-millisecond echo canceller that is suitable for canceling the local echo caused by a 2-to-4 wire hybrid and can achieve echo cancellation of approximately 30dB or more. Only the linear portion of the echo is cancelled, so circuits should be designed to minimize non-linearities.

  • Page 44: Voice Activation Detection (Vad), Comfort Noise Insertion (Cni)

    Normal Power and Power Saving Modes Power savings can be achieved during times of longer inactivity of the AMBE-2000™ chip by placing it into one of three available Low Power Modes. The chip can be placed into low-power and stand-by modes via hardware or software Control Words.

  • Page 45: Power Down

    Standard Sleep reset OR Control Word Power Down Control Word DVSI Confidential Proprietary, Subject to Change Visit us at www.dvsinc.com AMBE-2000™ Vocoder Chip Users Manual Version 4.92, June, 08 Return to Normal Wake Up Operation via Time Control Word RESETN 95 ms.

  • Page 46: Slip Enable

    In any real time communication system, clock skew issues must be anticipated to keep the flow of data smooth from one end of the system to the other. The SLIP_EN (pin 82) signal allows the encoder of the AMBE-2000™ to react to small slips in the encoder channel signals.
  • Page 47 Words as shown in Table 7D above, where the Channel Data is the compressed voice data being sent to the AMBE™ decoder. In the Periodic Slip Control method such a Slip Control Packet is input into the vocoder chip every N frames. The value of N must be selected by the design engineer to meet the following constraint: 0.25 >...
  • Page 48 The preferred method for using Slip Control Packets is to monitor the availability of data from the AMBE-2000™ vocoder chip and to only input Slip Control Packets into the data stream sent to the AMBE-2000™ as needed. Note that for this method slip control must be enabled (SLIP_EN is high) on the chip.
  • Page 49 AMBE-2000™ Vocoder Chip Users Manual Version 4.92, June, 08 DVSI Confidential Proprietary, Subject to Change Page 49 Visit us at www.dvsinc.com...

  • Page 50: Example A/D-D/A Usage

    CODEC_TX_DATA AMBE-2000 REFERENCE DATA The AMBE-2000™ sends the following configuration sequence to the AD73311 when CODEC_SEL [1-0]=01b: 0x8113, // write 13 to CRB of AD73311, MCD=1 (DMCLK=MCLK/2),SCD=0(SCLK=DMCLK/8) 0x82f9, // write f9 to CRC of AD73311, 5VEN, REFOUT, all Power ON...

  • Page 51: Example: Texas Instruments Tlv320Aic10 Usage

    The control registers in the TLV320AIC10 codec must be initialized for proper operation. The recommended procedure is to initialize the TLV320AIC10 by writing data to its 4 control registers through the DCSI port, while the AMBE-2000™ is held in reset. The timing for the DCSI port is shown in Figure 2.
  • Page 52 0x00 Table 1: Recommended TLV320AIC10 Configuration Data DVSI Confidential Proprietary, Subject to Change Visit us at www.dvsinc.com AMBE-2000™ Vocoder Chip Users Manual Version 4.92, June, 08 Notes: D4=1: select AUXP AND AUXM for ADC (Handset) D5=0: enable antialiasing filter D0=1: select 16 BIT data Format for DAC...
  • Page 53 CNTL_DATA [15:0] AIC_LOAD SCLK Figure 3: TLV320AIC10 Codec Configuration Detail Reference Materials: AMBE-2000™ Vocoder chips Users Manual: http://www.dvsinc.com/literature.htm TLV320AIC10 Data Sheet: http://www-s.ti.com/sc/ds/tlv320aic10.pdf TLV320AIC10 EVM User’s Guide: http://www-s.ti.com/sc/psheets/slwu003d/slwu003d.pdf Application Report – Understanding Data Converters: http://www-s.ti.com/sc/psheets/slaa013/slaa013.pdf DVSI Confidential Proprietary, Subject to Change Visit us at www.dvsinc.com...
  • Page 54 TLV320AIC10 Reference Schematic (Analog Section) 820pF 3.3VA 10uF Handset DVSI Confidential Proprietary, Subject to Change Visit us at www.dvsinc.com AMBE-2000™ Vocoder Chip Users Manual Version 4.92, June, 08 AD8544 100K 100K 2 nF 200pF 0.1uF 220K 5.6K 10uF VMID 4.7K 10uF 3.3VA...

  • Page 55: Configuring The Ad73311 For 3-Volt Operation

    CODEC_SEL [1-0] (pins 85,84) = 01,b Hold the CODEC_TX_DATA lines on the AMBE-2000™ in tri-state (in the circuit set the SDI bit to 0,b) during power up. While the AMBE-2000™ lines are in tri-state, send the desired configuration words from the DSP/Microcontroller/logic to the AD73311 (Reset timing constraints for the AD73311 must be met).
  • Page 56 The Analog Devices AD73311L is a low power 3 volt version of the AD73311. It is possible to use this part with the AMBE- 2000™ or AMBE-2020™ vocoder chip utilizing the method described above for sending alternate configuration words to the AD73311 CODEC. Table 3 lists alternate control words for configuring the AD73311L for use with the AMBE-2000™ or AMBE-2020™.
  • Page 57 AD73311 - Data Sheet http://www.analog.com/productSelection/pdf/AD73311_b.pdf AD73311L - Data Sheet http://www.analog.com/productSelection/pdf/AD73311L_a.pdf DVSI Confidential Proprietary, Subject to Change Visit us at www.dvsinc.com AMBE-2000™ Vocoder Chip Users Manual Version 4.92, June, 08 Page 57...

  • Page 58: Interfacing To The Texas Instruments Pcm3500 Codec

    Interfacing to the Texas Instruments PCM3500 Codec The Texas Instruments PCM3500 codec chip presents a simple low cost solution for use with DVSI’s AMBE-2000™ or AMBE-2020™ vocoder chips. This application note provides information on alternative methods of interfacing these components.
  • Page 59 47nF 3.3VA 10uF Handset 0.2uF 3.3VA 5.6K 4.7K 10uF AMBE-2000™ and AMBE-2020™ Vocoder Chip Interface Applications Note 2.2uF 2.1K 4.7uF 100nF Analog In 3.3 V 220K CODEC_TX/RX_CLK CODEC_TX/RX_STRB CODEC_TX_DATA 3.3VA CODEC_RX_DATA 3.3VA 10uF Figure 2 Page 59 of 67 3.3 V...
  • Page 60 Additional Reference Material AMBE-2000™ or AMBE-2020™ vocoder chip Users Manual http://www.dvsinc.com/literature.htm Application Report – Understanding Data Converters: http://www-s.ti.com/sc/psheets/slaa013/slaa013.pdf PCM3500 Data Sheet http://www-s.ti.com/sc/ds/pcm3500.pdf PCM3500 Evaluation Board http://www-s.ti.com/sc/psheets/sbau028/sbau028.pdf AMBE-2000™ and AMBE-2020™ Vocoder Chip Interface Applications Note Page 60 of 67 Jan 03...

  • Page 61: Expanded Tone Detection And Generation

    Expanded Tone Detection and Generation The AMBE-2000™ is capable of detecting and generating single tones as well as dual tones. The single tones span from 156.25 Hz to 3812.5 Hz in 31.25 Hz steps. Tone Index (Decimal) ……… 123-127 ………….
  • Page 62 AMBE-2000™ Vocoder Chip Users Manual Version 4.92, June, 08 Placing a logic high on pin 79 of either the AMBE-2000™ or AMBE-2020™ vocoder chips enables the soft decision error correction on the decoder. Enabling the soft-decision does nothing to the encoder packet. The packet will look like a normal encoded packet.
  • Page 63 Table 1. Soft-Decision Decoder Packet Word # DVSI Confidential Proprietary, Subject to Change Visit us at www.dvsinc.com AMBE-2000™ Vocoder Chip Users Manual Version 4.92, June, 08 Description Header always set to 0x13EC Power Control (8 bits) Rate info 0 Rate info 1...

  • Page 64: Special Rate 2350 Bps Voice / 50 Bps Fec Ambe-1000™ Vocoder Chip Compatible Mode

    Pin 73 Table 1. Compatible Mode Procedure Step 1. To enable the AMBE-2000/2020™ to interoperate with the AMBE-1000™ Vocoder Chip at the rate of 2350 bps voice + 50 bps FEC, first send the packet described in Table 2. Word #...
  • Page 65 Compatible Mode Procedure Step 3. After the packets detailed in Table 2 and Table 3 are sent into the AMBE-2000/2020™ Vocoder Chip the RIS bits in Control Word 2 must be set to 0x3 for each subsequent packet. If the rate is changed or the device is reset, the above procedure (steps 1, 2 and 3) must be repeated.

  • Page 66: History Of Revisions

    Added description of Decoder Silence Detect, Decoder Frame Repeat February 2005 April 2005 DVSI Confidential Proprietary, Subject to Change Visit us at www.dvsinc.com AMBE-2000™ Vocoder Chip Users Manual Version 4.92, June, 08 History of Revisions Description Initial Version Pin descriptions...
  • Page 67 Sept 07 Edited Table in Note 2 on page 14 4.91 March 08 Revised the AMBE-2000™ Vocoder Chip END USER License Agreement Revised Pin 86 VAD_EN pin Voice Activity Detection description to clearify 4.92 June 08 enable/disable and ON/OFF Control.

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