1. Manuals
  2. Brands
  3. Prism Sound Manuals
  4. Media Converter
  5. AD-2
  6. Operation manual

Prism Sound AD-2 Operation Manual

Dream series dual-rate a/d converter with super noise shaping and synchronous sample-rate conversion (src)
Hide thumbs
Table of Contents

Advertisement

Quick Links

Download this manual
Dual-rate A/D converter
with
Super Noise Shaping
and synchronous
Sample-Rate Conversion (SRC)
Operation Manual
Issue 0.2 11 August 1998

Advertisement

Table of Contents
loading
Need help?

Need help?

Do you have a question about the AD-2 and is the answer not in the manual?

Questions and answers

Related Manuals for Prism Sound AD-2

Summary of Contents for Prism Sound AD-2

  • Page 1 Dual-rate A/D converter with Super Noise Shaping and synchronous Sample-Rate Conversion (SRC) Operation Manual Issue 0.2 11 August 1998...

  • Page 2: Table Of Contents

    Unpacking your AD-2 Dual-rate A/D converter ....6 2.2. Using the AD-2 for the first time ......6 2.3.
  • Page 3 Prism Media Products Limited AD-2 Dual-rate A/D converter Operation Manual TECHNICAL SPECIFICATION ........39 7.1.

  • Page 4: Introduction

    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.

  • Page 5: Terminology For High-Sampling Rate Interfaces

    These recordings cannot be replayed or copied without a suitable D/A converter or format converter and sample-rate converter (for 44.1k/48k CD and DAT). In the AD-2 menu system, references to this mode of operation are made using the term ‘Split96'; in the Factory Presets the term ‘2wr’ (two-wire) is also used.

  • Page 6: 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.
  • Page 7 Prism Media Products Limited AD-2 Dual-rate A/D converter Operation Manual Issue 0.2 © Prism Media Products Limited 11 August 1998 Page 7 of 58...

  • Page 8: A-D Mode Factory Presets

    U IEC958/SPDIF U IEC958/SPDIF WCK may be any standard rate (32, 44.1, 48, 88.2 or 96kHz). If none is present, the AD-2 defaults to Internal sync. DRE modes are not included in the Factory Presets. See sections 3.8 and 4.6.
  • Page 9 Prism Media Products Limited AD-2 Dual-rate A/D converter Operation Manual 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.

  • Page 10: D-D Mode Factory Presets

    UIEC958/SPDIF U IEC958/SPDIF U IEC958/SPDIF 2x speed/1wire If no DI is present, the AD-2 defaults to Internal sync. DRE modes are not included in the Factory Presets.See sections 3.8 and 4.6. Issue 0.2 © Prism Media Products Limited 11 August 1998...

  • Page 11: Selecting One Of The Factory Preset Configurations

    AD-2. A useful check is to send a 0VU line-up tone. If all is well, this should illuminate the AD-2 meters up to the -14dB division (in practice the LED at -14 may be on OR off for nearly exact 0VU line-up with +18dBu headroom).

  • Page 12: Synchronization

    BNC WCK input connector. A wordclock signal may be provided at any of the standard rates and the AD-2 will lock to it even though its outputs may be running at a different, fixed sample rate. For more information about synchronization of the AD-2, see section 5.

  • Page 13: Introduction To The Setup Wizard

    The Setup Wizard will allocate Main Output to all output connectors. To use the Setup Wizard, press the <Setup Wizard> button on the far right of the AD-2 front panel and follow the prompts in the LCD display. The first prompt will be: * Setup Wizard * Enter to start.
  • Page 14 Prism Media Products Limited AD-2 Dual-rate A/D converter Operation Manual 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.

  • Page 15: Frequently-Asked Questions (Faqs)

    This means that a Digital Input (DI) signal is expected but not present or is incorrect.. In the default state of the AD-2, if an external Wordclock is not connected, this warning is shown accompanied by a solid ON “Local” LED and a flashing “WCK” LED.

  • Page 16: Can I Drive 2 Wire And 1-Wire 96Khz At The Same Time

    Prism Media Products Limited AD-2 Dual-rate A/D converter Operation Manual 3.4. 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.

  • Page 17: Can The Ad-2 Convert Up To 96Khz From 44.1Khz

    Press [9 9 ] until Main O/P Setup is displayed, then [Enter]. Use the [7 7 ] and [6 6 ] keys to select the desired high sampling rate, followed by [Enter] to confirm the selection. The AD-2 is now ready to up-convert using AES3 input on input XLR1 and generating 1-wire (2x speed) output on XLR1 and XLR2.

  • Page 18: Operation Reference

    4.1. General configuration rules The AD-2 is a powerful and flexible tool and these benefits bring with them a degree of complexity. In addition to the operating methods mentioned above, there are several guidelines that are worth remembering when trying to set up complex configurations.

  • Page 19: To Reset The Ad-2 To Its Factory Default State

    Setup Wizard as a base and then change the Auxiliary output and Output connector assignments using the Menu system. To use the Setup Wizard, press the <Setup Wizard> button on the far right of the AD-2 front panel and follow the prompts in the LCD display. The first prompt will be: * Setup Wizard * Enter to start.

  • Page 20: Program Level Meter

    Prism Media Products Limited AD-2 Dual-rate A/D converter Operation Manual 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.

  • Page 21: Store Controls

    The best way of using the AD-2 is to become familiar with the contents of the Factory Preset stores and to select the one which is the best fit with your requirement. Then you can customize it by changing just a few parameters.
  • Page 22 [8 8 ] or [9 9 ] keys, or by double pressing any other store button <1> to <4> or <Setup Wizard>]. Step 6 To load the store, when in preview mode, press the [Enter] key. This will set the AD-2 to the settings contained in the selected store. Issue 0.2 © Prism Media Products Limited...
  • Page 23 AD-2 Dual-rate A/D converter Operation Manual 4.5.2. Save settings to a user store Prior to saving the AD-2 settings to one of the user stores you will probably have created a custom configuration by one of the following methods: "...
  • Page 24 Prism Media Products Limited AD-2 Dual-rate A/D converter Operation Manual Step 8 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>...
  • Page 25 Prism Media Products Limited AD-2 Dual-rate A/D converter Operation Manual 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 ;note: the first character will be flashing...

  • Page 26: Menu System Operation

    4.6. Menu system operation The Menu system of the AD-2 provides access to all operating parameters so that custom configurations of both A-D and D-D modes can be created and preferences such as LED brightness and LCD contrast (and others) can be set.
  • Page 27 <1> to <4> or double- pressing the <Setup Wizard>. Alternatively, leave the controls until the AD-2 times out. display will revert to normal automatically after a preset time which can be set in the preferences menu (see below).
  • Page 28 When you have found the parameter that you want to change, use the [7 7 ] and [6 6 ] keys to select the setting that you want. Most AD-2 settings require confirmation of the change by pressing [Enter]. You will see that the new setting is then displayed on the first line of the display. You can then reverse out of the menus with [8 8 ] or wait for the unit to time out [or double-press any store button <1>...

  • Page 29: Menu System Reference

    Prism Media Products Limited AD-2 Dual-rate A/D converter Operation Manual 4.7. Menu system reference !!! [6 6 ] [6 6 ]back to Level Display Level Display Screen Warnings Screen Mode: A-D, D-D Sync Source: Int, DI Main Output Setup [Enter] fs: 44.1, 48, 88.2, 96, =DI...

  • Page 30: System State Indicator Leds

    Prism Media Products Limited AD-2 Dual-rate A/D converter Operation Manual 4.8. 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.
  • Page 31 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. For information about digital inputs, see section 6.2.
  • Page 32 Prism Media Products Limited AD-2 Dual-rate A/D converter Operation Manual “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.

  • Page 33: Synchronization Modes

    If the Sync Mode is set to ‘Int’ in D-D Mode, then the AD-2 acts as a clock master: i.e. it determines its output data rates from its high-precision internal clock, even though it must accept its digital input data at the correct sampling rate (or, actually, at a standard rate in fixed relationship to its output rate, since it may be rate-converting).
  • Page 34 AD-2 Dual-rate A/D converter Operation Manual 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.

  • Page 35: Connectors

    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.

  • Page 36: Digital Output Connectors

    88.2kHz or 96kHz data. The format is described in [Ref.8]. 6.3. Digital output connectors The AD-2 Dual-rate A/D converter can generate digital audio outputs in a variety of formats. These are: AES3 professional AES/EBU on an XLR connector;...
  • Page 37 Prism Media Products Limited AD-2 Dual-rate A/D converter Operation Manual ‘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.

  • Page 38: Connector Table

    Prism Media Products Limited AD-2 Dual-rate A/D converter Operation Manual 6.5. Connector table Viewed from the rear, left to right, the connectors are as follows: IEC320 - 3 pin Mains power inlet XLR-Female Analogue Channel A or Left XLR-Female Inputs...

  • Page 39: Technical Specification

    Prism Media Products Limited AD-2 Dual-rate A/D converter Operation Manual 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.
  • Page 40 Prism Media Products Limited AD-2 Dual-rate A/D converter Operation Manual Any spurious levels: <-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 (50Hz) >85dB...

  • Page 41: Analogue Inputs

    Prism Media Products Limited AD-2 Dual-rate A/D converter Operation Manual Level-dependent logarithmic gain linearity: << 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.

  • Page 42: D-D Mode Performance Specification

    7.3. 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.

  • Page 43: Digital Inputs

    Digital input resolution/wordlength: 24 bits The AD-2 resolves all the data bits of the digital interface formats. Input signals are not truncated and hence truncation distortion does not occur. Note: In conformance with the digital audio interface specifications, all signals with professional channel status that indicate that the auxiliary audio data bits do not carry the main audio signal will have the lower 4 bits masked off to avoid non-audio data adding to the audio.
  • Page 44 Prism Media Products Limited AD-2 Dual-rate A/D converter Operation Manual 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.
  • Page 45 Such equipment will often require delays to be carefully matched before it will work correctly. The AD-2 Dual- rate A/D converter uses a rugged algorithm to correctly decode SDIF data independent of delays or phase.

  • Page 46: Digital Outputs

    This can be done by setting the output word-length of the AD-2 appropriately. The word-length reduction may be achieved in a fully compatible way by using dither or SNS noise-shaping. Alternatively the DRE coding system may be used to store high resolution audio onto 16-bit channels.
  • Page 47 Prism Media Products Limited AD-2 Dual-rate A/D converter Operation Manual 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.
  • Page 48 Prism Media Products Limited AD-2 Dual-rate A/D converter Operation Manual 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.

  • Page 49: Synchronization

    Prism Media Products Limited AD-2 Dual-rate A/D converter Operation Manual 7.5.11. 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.

  • Page 50: Power

    Prism Media Products Limited AD-2 Dual-rate A/D converter Operation Manual 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.
  • Page 51 Prism Media Products Limited AD-2 Dual-rate A/D converter Operation Manual 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.

  • Page 52: Performance Plots

    8.1. Dynamic Range 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 130.70dB in the test above)

  • Page 53: Thd+N

    8.2. 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.

  • Page 54: Src (Sample-Rate Converter)

    Operation Manual 8.3. SRC (Sample-rate converter) Figure 21 shows a THD+n plot of the AD-2 in D-D mode, sample-rate-converting a 24- bit, 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.

  • Page 55: Sns Noise Shaper Characteristics

    Prism Media Products Limited AD-2 Dual-rate A/D converter Operation Manual SNS NOISE SHAPER CHARACTERISTICS Issue 0.2 © Prism Media Products Limited 11 August 1998 Page 55 of 58...
  • Page 56 Prism Media Products Limited AD-2 Dual-rate A/D converter Operation Manual Issue 0.2 © Prism Media Products Limited 11 August 1998 Page 56 of 58...

  • Page 57: Electromagnetic Compatibility

    Prism Media Products Limited AD-2 Dual-rate A/D converter Operation Manual 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.

  • Page 58: August 1998

    Prism Media Products Limited AD-2 Dual-rate A/D converter Operation Manual REFERENCES 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) AES11-1991 - `AES Recommended Practice for Digital Audio Engineering - Synchronization of Digital Audio Equipment in Studio Operations' J.
  • Page 59 Prism Media Products Limited William James House Cowley Road Cambridge CB4 0WX UK E-mail : sales@prismsound.com Web : www.prismsound.com Tel: +44 (0)1223 424988 Fax: +44 (0)1223 425023...

Table of Contents