ULTRAMATCH PRO SRC2496

the signal has been processed with this technique. It is however NOT a modification of the audio signal, but only of the emphasis marker contained in the digital data stream.

So much for the theory. In practice, a lit EMPHASIS LED does not necessarily show that the emphasis function has really been applied. In several situations the emphasis bit was set during the mastering and editing process due to defective hardware/ software—without any treble boost applied. This error usually remains undetected when the material is transferred, because modern DAT recorders no longer have an emphasis indicator for reasons of rationalization. When the master tape—usually only monitored briefly on the DAT recorder due to lack of time—arrives at the customer’s end, it gives him a big surprise: The treble range has been cut in the DAT recorder by more than 10 dB, which cannot be undone and results in a dull sound that lacks brilliance in the treble range. It is for this reason that we equipped the ULTRAMATCH PRO both with an emphasis status LED and with an additional switch for manual correction of the emphasis bit setting.

3.5 Line booster, signal refresher

Longer cable lengths or the use of a digital patchbay lead to deterioration of signal quality, which may result in a higher noise floor or even connection failures. Using special input circuitry your ULTRAMATCH PRO removes jitter, interference and level loss, thus restoring the signal to perfect quality. As a consequence, you can also use the SRC2496 to refresh the signal over longer cable lengths or to restore attenuated and distorted signals.

3.6 Correcting incorrect sample rates

The sample rate of any equipment is subject to fluctuation due to temperature and ageing effects. Normally, an automatic locking circuit ensures reliable operation even with varying or slightly fluctuating clock signals. If such fluctuations exceed a certain level, however, the receiving equipment cannot be synchronized any longer to the clock rate supplied and therefore fails to function properly.

Your ULTRAMATCH PRO is totally free from such restrictions, as it works over the entire bandwidth from 31 to 100 kHz, rather than only within a small range around the actual sampling rate. The signal output by the SRC2496 is always synchronized correctly to the value selected. Thus, you can use your ULTRAMATCH PRO to “rescue” and work with sampling rates that have been modified deliberately (vari-pitch function on sampling keyboards or CD players) or fail to fall within the adjusted range due to rate fluctuations.

3.7 Vari-speed application

There are several reasons for modifying the speed of a digital playback, e.g. to change the pitch or synchronize the playback to other equipment. In such cases, the ULTRAMATCH PRO can track the sampling rate as it changes and then output the signal with a fixed rate of 44.1 kHz (or any other selectable or wordclock- defined value). Thus, it reliably removes sampling rate fluctuations, which could otherwise make it impossible to process the digital audio material any further in the digital domain.

+At its digital input, the ULTRAMATCH PRO accepts sampling rate fluctuations of up to ±12% from the adjusted sampling rate, without producing any distortion at its output. When things get worse, the connection will not be interrupted, but temporary drops in the signal quality (distortion) may occur.

3.8 Format converter

Digital data transfer is frequently affected by problems with the format required. While some devices specifically need S/PDIF signals on the input side, others can only output

AES/EBU. With the SRC2496 this problem is now history. The input of your ULTRAMATCH PRO readily accepts any standard used today. On the output side, you can select either AES/EBU or S/PDIF, so that it is just a matter of one key press to realize the successful transfer of your audio material.

3.9 Format interface

Many CD players have no coaxial but only an optical output. Some DAT recorders, on the other hand, only have a coaxial input. Digital interface cards for personal computers are usually equipped either with optical or coaxial connectors. So, when you try to transfer data from one unit to another you are likely to encounter incompatibility problems, in that one unit has an optical connector, while the other has a coaxial RCA connector. Connection to professional equipment is difficult because of the XLR connectors used there, or even impossible if it features optical interfaces.

Such incompatibilities between inputs and outputs are definitely a thing of the past with the ULTRAMATCH PRO. For example, if the CD player only has an optical digital output, while the DAT recorder is equipped with a coaxial RCA input, your SRC2496 will easily eliminate the resulting connection problems with its three inputs and outputs in all formats. Your ULTRAMATCH PRO allows for interconnecting virtually all equipment that is available on the market today!

3.10 Patchbay/splitter

The digital outputs of your ULTRAMATCH PRO can all be operated at the same time. In this case, the input selector functions as a kind of miniature patchbay determining which signal is sent to the output. It is not necessary to switch-over the output, because you can freely select on the down-stream devices which signal to accept (example: recording active/inactive). Therefore, the outputs of the ULTRAMATCH PRO carry the identical signal all the time and are operative simultaneously.

The parallel operation of all three outputs enables you to use your SRC2496 as a splitter, which is useful for copying material to several DAT recorders. With some special types of equipment in particular that does not allow for looping through the digital data from the input to the output, this useful function makes it possible to split up the signal.

4.TECHNICAL BACKGROUND

4.1A short digression into digital sample rateconversion

In the past, the conversion of various sample rates into a fixed value necessitated a whole rack full of components and even then had some disadvantages that could be measured as increased noise, distortion or undesirable mirror frequencies (high-frequency chirping). On the other hand, the sampling rate converter chip installed in the ULTRAMATCH PRO converts in real time and with 24-bit precision. Its processing is absolutely inaudible and can only be identified with state-of-the-art, extremely expensive measuring instruments.

The functional principle is difficult to comprehend, even for professionals. That is why we are presenting you with an equivalent model, which describes the processes taking place in the processor in an easily understandable manner. The processor carries out an oversampling at the input signal. Between each sample, more samples are inserted, thereby significantly increasing the number of sampling points by filling in the gaps. Subsequently, the signal passes through a variable low-pass filter, which ensures that the correct limit, below which no problems with mirror frequencies (aliasing) occur, is observed. Then, the number of sampling points is distributed in such a way as to obtain the desired sampling rate at the output. This enormous oversampling allows the SRC processor to achieve excellent precision in the complete conversion range. Moreover, it also simultaneously eliminates any jitter present in the input signal.

4. TECHNICAL BACKGROUND

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