Dual-rate A/D converter with Super Noise Shaping and synchronous Sample-Rate Conversion (SRC) Operation Manual Issue 0.
Prism Media Products Limited Operation Manual AD-2 Dual-rate A/D converter CONTENTS 1. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1. Notational conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.2. Terminology for high-sampling rate interfaces . . . . . . . . . . . . . . . . . . 5 2. GETTING STARTED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.1.
Prism Media Products Limited Operation Manual AD-2 Dual-rate A/D converter 7. TECHNICAL SPECIFICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1. A-D mode Performance Specification . . . . . . . . . . . . . . . . . . . . . . . . 7.2. Analogue Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3. D-D mode Performance Specification . . . . . . . . . . . . . . . . . . . . . . . . 7.4. Digital Inputs . . . . . . . . . . . . . . . . . . . . .
Prism Media Products Limited Operation Manual 1. AD-2 Dual-rate A/D converter INTRODUCTION To get started immediately, please turn to page 6. The AD-2 Dual-rate A/D converter is intended for professional audio use in applications where a very high level of performance is required. The high performance of the AD-2 was a key design objective and care should be taken when making comparisons to check that consistent measurement units and methods are employed.
Prism Media Products Limited Operation Manual 1.2. AD-2 Dual-rate A/D converter Terminology for high-sampling rate interfaces A variety of terms are in use regarding high sampling-rate interfaces. For more information about these interfaces see sections 6.2 and 6.3. 1.2.1. Split96 or 2-wire AES3 interfaces For recording applications requiring 96 or 88.2kHz sampling a solution is to use two channels of a 44.1/48 kHz device for each audio channel at the higher rate.
Prism Media Products Limited Operation Manual AD-2 Dual-rate A/D converter 2. GETTING STARTED 2.1. Unpacking your AD-2 Dual-rate A/D converter Check that you have the correct power lead with your AD-2 and that they and the packaging are undamaged. Check that your unit is set for operation at the mains voltage appropriate for your area. See section 7.7 for more details.
Prism Media Products Limited Operation Manual Issue 0.
Prism Media Products Limited Operation Manual 2.3. AD-2 Dual-rate A/D converter A-D mode Factory Presets A-D MODES Store Store number 1 2 3 4 A-D:96k,24b 2XLR A-D:96k,24b 1XLR AD:44k1,24b&16b A-D:96/24, 44/16 WCK or INT* WCK or INT* WCK or INT* WCK or INT* WCK BNC WCK BNC WCK BNC WCK BNC OFF** OFF** OFF** OFF** +18dBu*** +18dBu*** +18dBu*** +18dBu*** 0dB*** 0dB*** 0dB*** 0dB*** Right ch. trim 0dB*** 0dB*** 0dB*** 0dB*** Sample Rate 96.0 kHz 96.0 kHz 44.1 kHz 96.
Prism Media Products Limited Operation Manual *** AD-2 Dual-rate A/D converter The default line-up setting is digital full code (0dBFS) at +18dBu with no fine trim. Setting of line-up by stores is possible, but is initially disabled (preferences menu) see section 4.6. Issue 0.
Prism Media Products Limited Operation Manual 2.4. AD-2 Dual-rate A/D converter D-D mode Factory Presets D-D MODES Store Store number 1 2 3 4 SRC:AES644,24&1 6 SRC:2wr644,24&1 6 SNS2:AES616b,AE S SNS2:2wr616b,AE S DI* DI* DI* DI* AES/XLR1 32, (44.1), 48, 88.2, 96kHz 2-wire/XLR1&2 88.2, 96kHz AES/XLR1 32-96kHz 2-wire/XLR1&2 88.2, 96kHz DRE decode OFF** OFF** OFF** OFF** Sample Rate 44.1 kHz 44.1 kHz As Input (32-96kHz) 88.2 or 96.
Prism Media Products Limited Operation Manual 2.5. AD-2 Dual-rate A/D converter Selecting one of the Factory Preset configurations If the configuration at power-up is not suitable for your application, you may find that another Factory Preset will be satisfactory. 2.5.1.
Prism Media Products Limited Operation Manual AD-2 Dual-rate A/D converter 2.6.1. Adjust the maximum analogue input level (line-up) Step 1 repeatedly press the [9 9] button in the Menu panel until A-D Mode Setup is displayed in the top line of the display Step 2 press “Enter” Step 3 Use the[6 6] and [7 7] buttons to set the desired maximum input level.
Prism Media Products Limited Operation Manual 2.8. AD-2 Dual-rate A/D converter Introduction to the Setup Wizard The Setup Wizard helps you create custom A-D configurations. It provides choices of sample rate, wordlength, synchronization, maximum input level and digital interface format. The Setup Wizard will allocate Main Output to all output connectors. To use the Setup Wizard, press the button on the far right of the AD-2 front panel and follow the prompts in the LCD display.
Prism Media Products Limited Operation Manual AD-2 Dual-rate A/D converter At this point, if you have not already saved any configurations to user stores, all of the store LEDs above buttons <1> to <4> will be flashing. If you do not wish to store your setup, simply press [Enter], ignore the prompt to select a store and press [Enter] again. You will see: Setup not Saved Then press [Enter] to finish.
Prism Media Products Limited Operation Manual 3. AD-2 Dual-rate A/D converter FREQUENTLY-ASKED QUESTIONS (FAQs) This section provides several ‘how to ....’ answers in response to a range of frequentlyasked questions. 3.1. What do the flashing !!! Characters mean in the display? These indicate a warning condition and further explanation can be seen by pressing [6 6].
Prism Media Products Limited Operation Manual 3.4. AD-2 Dual-rate A/D converter Can I drive 2 wire and 1-wire 96kHz at the same time? Yes. You could use any of the A-D Factory Presets 1, 2 or 4 as a base or you could start with the Set-up Wizard and set 96k 1-wire 24-bit output. Then, you must modify the resulting setup to obtain the formats you need. Starting from A-D Factory Preset 2; Factory Preset Store 2 places the Main Output on the XLR and BNC connectors in 1wire (2x speed) AES-3id format.
Prism Media Products Limited Operation Manual 3.6. AD-2 Dual-rate A/D converter Can the AD-2 convert up to 96kHz from 44.1kHz? Yes. Use D-D Factory Preset Store 1 as a base. (Store 2 will be less useful as it specifies 2-wire input and this would need to be changed.) Press , and then <1>. Press [Enter] to load the store. See section 2.4 for details of D-D Factory Preset stores. Now change the output sample rate from the preset 44.1kHz to 96 or 88.2kHz.
Prism Media Products Limited Operation Manual 4. AD-2 Dual-rate A/D converter OPERATION REFERENCE To reduce front-panel and operational complexity, the control of the AD-2 is provided by means of various preset configurations complemented by a menu system which allows access to all operating parameters individually.
Prism Media Products Limited Operation Manual 4.2. AD-2 Dual-rate A/D converter To reset the AD-2 to its factory default state USE THIS WITH CARE, AS THE USER STORES WILL BE CLEARED. Use the [9 9] key to enter the menu system and hold it down until Preferences is displayed. Press [Enter], then press [9 9] until you see: Reload Factory Defaults/Stores? Press [Enter] and at the prompt Enter to Accept press [Enter] again. 4.3. Setup Wizard The Setup Wizard helps you create custom A-D configurations.
Prism Media Products Limited Operation Manual AD-2 Dual-rate A/D converter Press [Enter] and you will see: Empty stores -> are flashing... At this point for each empty user store, the corresponding LED above the store button will be flashing. If you do not wish to store your setup, simply press [Enter], ignore the prompt to select a store and press [Enter] again. You will see: Setup not Saved Then press [Enter] to finish. Alternatively..
Prism Media Products Limited Operation Manual AD-2 Dual-rate A/D converter will still be clearly visible]. Also, the text display of peak level is updated sufficiently slowly that the values can be read while the signal amplitude is changing. Using the [Enter] key the hold mode can be toggled between normal and indefinite hold. For indefinite hold mode, the peak level displayed in the LCD will not decay but will be replaced each time higher peak levels are detected.
Prism Media Products Limited Operation Manual AD-2 Dual-rate A/D converter Store system organization MODE Store No. 1 2 3 4 A-D Factory Preset Factory Preset Factory Preset Factory Preset A-D User User User User D-D Factory Preset Factory Preset Factory Preset Factory Preset D-D User User User User For details of the Factory Preset stores, see sections 2.3 and 2.4. 4.5.1.
Prism Media Products Limited Operation Manual AD-2 Dual-rate A/D converter 4.5.2.
Prism Media Products Limited Operation Manual Step 8 4.5.2.2. AD-2 Dual-rate A/D converter Press [Enter] again to confirm. Your current settings will be stored. Alternatively, press [8 8] or [9 9] or the button under the flashing store LED to cancel the store operation [or double press any other store button <1> to <4> or .] Saving over an existing store using the default store description Step 6 Change the store operation from ‘Load’ to ‘Save’ by pressing the [6 6] key.
Prism Media Products Limited Operation Manual AD-2 Dual-rate A/D converter A default store description will be displayed in the top line of the display with a prompt to continue, such as: A-D User #1 [fns] Enter=End Step A ;note: the first character will be flashing Optional : You may clear the description or select the default by pressing the [7 7] key. The [7 7] and [6 6] keys are used to move the character edit cursor along the display.
Prism Media Products Limited Operation Manual AD-2 Dual-rate A/D converter 4.5.3. Character set for store descriptions 6 ! @ _ ` “ # $ % & ‘ ( ) * + , - . / 0 1 2 3 4 5 6 7 8 9 : ; < = > ? A B C D E F G H I J K L M N O P Q R S T U V W X Y Z [ - ] a b c d e j | } f g h I k l m n o p q r s t u v w x y z { ^ 4.5.4. Editing the text description of a user store This is performed by first loading the store as described in section 4.5.
Prism Media Products Limited Operation Manual AD-2 Dual-rate A/D converter A string of exclamation marks !!! may be seen from time to time at the top right of the LCD display. This indicates a warning condition and the detail of the warning(s) can be inspected using the [6 6] key. If more than one warning condition is present, the various conditions will be displayed in rotation on the bottom line of the display. Press the [6 6] key again to return to the normal Level: display. 4.6.2.
Prism Media Products Limited Operation Manual 4.6.2.2. AD-2 Dual-rate A/D converter Parameter selections These display the parameter description and current setting. Example: Mode: A-D D-D A-D ; this allows setting of A-D or D-D mode, and ; shows that A-D is selected. The A-D on the top line is the current setting. On the bottom line is the set of choices.
Prism Media Products Limited Operation Manual 4.7. AD-2 Dual-rate A/D converter Menu system reference Level Display Screen !!! [6 6] Warnings Screen [6 6]back to Level Display Mode: A-D, D-D Sync Source: Int, DI Main Output Setup [Enter] fs: 44.1, 48, 88.2, 96, =DI Wordlength: 16b, 20b, 24b Quantizer: Flat, SNS1, SNS2, SNS3, SNS4 DRE Encode: Off, On Aux Output Setup [Enter] fs: 32, 44.1, 48, 88.
Prism Media Products Limited Operation Manual 4.8. AD-2 Dual-rate A/D converter System State Indicator LEDs In general the LED indications are quite self-explanatory but there are some which deserve further explanation. 4.8.1. Flashing LED indicators In general a flashing indicator provides a warning of some desired condition which is not attained or is not attainable. Common examples are : " Synchronization set to external WCK and none connected.
Prism Media Products Limited Operation Manual AD-2 Dual-rate A/D converter 4.8.2. Mode indicators There are two indicators in this group and they show the current mode of the AD-2: A-D or D-D. 4.8.3. Sync/DI indicators These indicate if the synchronization source is internal or external and if external, the type of synchronizing signal. If the AD-2 is in D-D mode, the input signal format is indicated. For more information about synchronization modes, see section 5.
Prism Media Products Limited Operation Manual AD-2 Dual-rate A/D converter “Auto” indicates the state of the auto-dither system, which can intelligently set itself on or off according to various conditions such as an input of digital zero or input of a wordlength less than or equal to the output wordlength. For more information see section 7.3.2. 4.8.6.
Prism Media Products Limited Operation Manual 5. AD-2 Dual-rate A/D converter SYNCHRONIZATION MODES In A-D mode, the AD-2 Dual-rate A/D converter can be operated as either a clock master or a clock slave. This is determined by the setting of the ‘Sync Mode’ menu. If the Sync Mode is set to ‘Int’, then the Main and Aux output rates are set to the rates requested in their respective menus, and are referenced to the AD-2s internal precision reference.
Prism Media Products Limited Operation Manual AD-2 Dual-rate A/D converter Operating the AD-2 as a clock master in D-D Mode may be desirable in a number of situations, such as when processing the output of a digital audio workstation, or when connected to an A-D converter with a poor-quality clock.
Prism Media Products Limited Operation Manual 6. CONNECTORS 6.1. Analogue input connectors AD-2 Dual-rate A/D converter Conventional connections from a balanced analogue source should use a screened twisted pair lead. The AD-2 input pins 2 (+) and 3 (-) should be wired to the two conductors of the pair and pin 1 to the cable screen. The other end of the cable should be connected in a similar manner with the screen connecting to the chassis of the source.
Prism Media Products Limited Operation Manual AD-2 Dual-rate A/D converter The desired digital input format is selected in the 'D-D Mode Setup' menu. See sections 4.6 and 4.7. Note on Split96 operation: 'Split96' is a format for passing hi-sampled (88.2kHz or 96kHz) signals on AES3 or AES-3id carriers at conventional bit-rates. This is achieved by using a single AES3 carrier per hi-rate channel (it would normally carry a stereo channel).
Prism Media Products Limited Operation Manual AD-2 Dual-rate A/D converter ‘Screen' connects directly to the chassis for the digital XLR outputs and all BNC connectors. Screen connects via a capacitor to the chassis for the digital XLR inputs. The RCA digital coaxial connections are transformer isolated with the screen coupled to the chassis using a capacitor at the connector. The analogue input connector screens are connected to the chassis via a parallel combination of resistor and capacitor.
Prism Media Products Limited Operation Manual 6.5.
Prism Media Products Limited Operation Manual 7. AD-2 Dual-rate A/D converter TECHNICAL SPECIFICATION Specifications quoted in this section are to AES17-1991 (ANSI S4.51-1991) [Ref. 3], band-limited 20Hz-20kHz, at 96kHz sampling rate and output resolution of 24-bits, except where stated. Analogue specifications are quoted with analogue input sensitivity set to +18dBu (for digital full scale output) except where stated, and after a 30 minute warm-up period.
Prism Media Products Limited Operation Manual Any spurious levels: AD-2 Dual-rate A/D converter <-112dBFS signals to -1dBFS <-130dBFS signals below -20dB FS <-140dBFS signals below -60dB FS Note: Highest level of any harmonic distortion component 7.1.2. Interference susceptibility CMRR: >110dB >85dB (50Hz) (15kHz) Crosstalk: <-130dB <-140dB (50Hz, -1dBFS in either channel, other terminated) (15kHz, -1dBFS in either channel, other terminated) 7.1.3.
Prism Media Products Limited Operation Manual Level-dependent logarithmic gain linearity: AD-2 Dual-rate A/D converter << 3dB at -144dBFS Note: This is a measurement of the output level of a 996.115Hz tone with respect to the input level. The output level at 997Hz is measured using 32 averages of an 8192 point FFT with a rectangular window. This method has much higher resolution than the test in AES17, which specifies a third-octave band-pass filter to eliminate noise.
Prism Media Products Limited Operation Manual 7.3. AD-2 Dual-rate A/D converter D-D mode Performance Specification 7.3.1. General With the input and output sample-rates synchronised, the D-D path of the AD-2 is transparent to 24-bit audio data, unless redithering is selected. Dither can be selected as 'flat' i.e. optimal triangular-probability-density-function (TPDF) unweighted noise, or one of four proprietary noise-shaper (SNS) characteristics may be selected.
Prism Media Products Limited Operation Manual AD-2 Dual-rate A/D converter Roll-off frequencies: 32kHz (lesser of input and output) rate: >14.5kHz (±0.05dB) >14.95kHz (-3dB) 44.1kHz (lesser of input and output) rate:>19.5kHz (±0.05dB) >20.25kHz (-3dB) 48kHz (lesser of input and output) rate: >20.0kHz (±0.05dB) >21.20kHz (-3dB) 88.2kHz (lesser of input and output) rate:>32.0kHz (±0.05dB) >33.25kHz (-3dB) 96kHz (lesser of input and output) rate: >35.0kHz (±0.05dB) >36.35kHz (-3dB) 7.4. Digital Inputs 7.4.
Prism Media Products Limited Operation Manual AD-2 Dual-rate A/D converter 7.4.3. Optical input: This input is physically compatible with the Toshiba ‘TOSLINK' fibre-optic connector, and data encoded according to professional (AES3-1992) or consumer (IEC958) formats is correctly decoded. 7.4.4. Coaxial (RCA) consumer input: Input impedance: 75S.
Prism Media Products Limited Operation Manual AD-2 Dual-rate A/D converter implementations of this interface do not use the synchronization pattern to identify the sample word boundary. Such equipment will often require delays to be carefully matched before it will work correctly. The AD-2 Dualrate A/D converter uses a rugged algorithm to correctly decode SDIF data independent of delays or phase. 7.4.6.
Prism Media Products Limited Operation Manual AD-2 Dual-rate A/D converter Note: Jitter tolerance is a measure of the ability of a receiver to correctly decode a digital interface signal which has jitter. Like most other jitter parameters it is normally measured in unit intervals. A unit interval (UI) corresponds to the smallest nominal time interval in the interface signal, for the AES3 or IEC958 interface formats there are 128 unit intervals per sample. Therefore at a sample frequency of 44.
Prism Media Products Limited Operation Manual AD-2 Dual-rate A/D converter 7.5.4. RCA coaxial consumer format (IEC958) This conforms with the unbalanced interface defined in IEC958 ed.1 clause 5.3 and IEC958 ed.2 part 3. Electrically, it is floating with the screen capacitively coupled to the chassis. It carries consumer format channel status, see section 7.5.12. Output impedance: Output level: Rise/fall time: 75 S ± 10% 0.5 V ± 10% (terminated) 22 ns ± 20% (terminated) 7.5.5.
Prism Media Products Limited Operation Manual AD-2 Dual-rate A/D converter Note: J17 emphasis cannot be indicated on the SDIF-2 outputs. 7.5.7. Coaxial SDIF-2 (Sony) wordclock format This output carries a TTL level square wave at the sample rate. The rising edge coincides with the start of a sample frame on the digital outputs.
Prism Media Products Limited Operation Manual 7.5.11. AD-2 Dual-rate A/D converter User bit on AES3 and IEC958 format digital outputs In A-D mode the output user data bit is zero. In D-D mode the user data from the input is passed through to the output. This allows D-D processes, such as SNS noise shaping, to be performed with CD or DAT subcodes intact. If the selected input is SDIF-2 format then the user data bit is zero. 7.5.12.
Prism Media Products Limited Operation Manual AD-2 Dual-rate A/D converter Internal high-precision clock accuracy: ±5 ppm D-D mode reference-to-input timing variation, before sample slip: ±25% of sample period Note: The AES11-1991 synchronization standard [2] requires an input synchronization window of ±25% of a sample period without hysteresis. 7.7. Power 7.7.1. Mains voltage: Externally set using selector as follows: Nominal setting '100V' '120V' '220V' '240V' 7.7.2. Consumption: 7.8.
Prism Media Products Limited Operation Manual AD-2 Dual-rate A/D converter There are five fuses internal to the unit, located close to the main heatsink. If these fuses have blown, a fault has occurred and the unit should be returned to the manufacturer or agent for service. The fuse types and applications are: F3 F4, F5 Type: 2AT - F1, F2 Type: Analogue input supplies 0.5AT Wickman TR5 subminiature type no. 19372K/500mA Issue 0.
Prism Media Products Limited Operation Manual 8. PERFORMANCE PLOTS 8.1. Dynamic Range AD-2 Dual-rate A/D converter Figure 19 shows a Dynamic Range plot of the AD-2 in A-D mode sampling at 96kHz. Figure 21: A-D mode Dynamic Range, at +28dBu sensitivity, 1kHz sine @ -60dBFS Apart from its unrivalled dynamic range (measured as 130.
Prism Media Products Limited Operation Manual 8.2. AD-2 Dual-rate A/D converter THD+n Figure 20 shows a THD+n plot of the AD-2 in A-D mode sampling at 96kHz. Figure 22: A-D mode THD+n, at +18dBu sensitivity, 1kHz sine @ -1dBFS Although the -108.59dBFS full-scale THD+n figure is, in itself, state-of-the-art, the absence of aharmonic spuriae gives the large-signal handling of AD-2 an entirely analogue quality. Issue 0.
Prism Media Products Limited Operation Manual 8.3. AD-2 Dual-rate A/D converter SRC (Sample-rate converter) Figure 21 shows a THD+n plot of the AD-2 in D-D mode, sample-rate-converting a 24bit, 96kHz-sampled 1kHz full-scale sinewave to 44.1kHz sampling rate. Figure 23: D-D SRC mode THD+n, 96kHz-to-44.1kHz, 1kHz sine @ 0dBFS The largest spurious component in the test above is -157.63dBFS.
Prism Media Products Limited Operation Manual 9. AD-2 Dual-rate A/D converter SNS NOISE SHAPER CHARACTERISTICS Issue 0.
Prism Media Products Limited Operation Manual Issue 0.
Prism Media Products Limited Operation Manual 10. AD-2 Dual-rate A/D converter ELECTROMAGNETIC COMPATIBILITY This equipment is intended for use in an electromagnetically controlled environment. To maintain the performance specification it should not be subject to strong magnetic fields (such as in the immediate vicinity of a power amplifier or cathode ray tube) and all connections should be terminated as described in the relevant sections of this manual.
Prism Media Products Limited Operation Manual AD-2 Dual-rate A/D converter 11. REFERENCES [1] AES3-1992 - ` Recommended Practice for Digital Audio Engineering - Serial Transmission Format for Two-Channel Linearly Represented Digital Audio Data' J. Audio Eng. Soc., Vol 40 No. 3, pp 147-165 (June 1992) [2] AES11-1991 - `AES Recommended Practice for Digital Audio Engineering - Synchronization of Digital Audio Equipment in Studio Operations' J. Audio Eng. Soc., Vol. 39 No.
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