DIGICheck's Global Level Meter displayes all available channels of the the interface simultaneously. This function is mainly intended as fast overview of current configuration and input signals. Channels with invalid input signals will be greyed out.
Level Meter Setup
The visible display range can be set between 0 and -160 dBFS. The measurement includes the whole range available from the received audio bit resolution, displayed in 0.1 dB steps. The change in color is defined in 'Warning Level'. Set to 0 dB a color change is only performed on the highest peak hold step - when 'Over' is detected.
The number of consecutive full scale samples for an 'Over' indication can be defined between 1 and 20. As the display of a phase relationship makes no sense below a certain threshold the correlator's display will be turned off. The number of LEDs in the Correlation Meter is also configurable in a wide range.
Channel Status Display / User bits
This function decodes and displays the channel status information contained in the SPDIF signal. In addition the real sample rate is measured with an accuracy of ± 100 Hz. A printing function provides a hardcopy of the channel status.
Even if you're not a super-duper technician you can gain useful information from this table.
Incompatibilities among digital devices are explained by a set 'Emphasis' or an active copy protection (field 'SCMS'.)
No sound from the CD-player? Perhaps the CD is full of scratches, showing 'Data Invalid' (resulting in an automatic mute of the DA-converter.)
When connecting a CD-player or a DAT-recorder parts of the subcode (coded into the user bits) will be shown in the 'Validity-Bit' field. The name changes to 'Validity-Bit/CD-Subcode' or 'Validity-Bit/DAT-Subcode' and shows track number, index and current play time.
From the DAT's subcode the Start-ID (not track number!) is presented whenever one occurs. Of course ALL information in the subcode may be decoded thanks to the 32 bit mode of the DIGI96 series, but this is only an example.
A professional hard disk recording software might use this information when transferring a 2 hour DAT tape into the PC to automatically set markers at the begin of each track (at each Start-ID.)
Bit Statistic & Noise
This function shows the state of the audio bits. Three states are detected: always low (0), alternating and always high (1.) Alternating means the bit is in use, zero indicates unused bits and permanent one is often caused by a defective AD-converter.
The Bit Statistics allows to determine the real resolution or word length of audio signals, for example at the output of A/D-converters, mixing desks and effects devices. Audio data will be indicated green (normal, bit used), otherwise blue (permanent 0, bit not used). In case of permanent 1 (error or DC) the color changes to red. The normal state of the Channel Status bit and the Validity bit is green, permanent values (red) indicate an error or distorted audio data
Glossary:
Crest value: Ratio between peak and RMS value. Music with small crest value is louder than one with a high crest value.
dBFS: deci Bel Full Scale. Logarithmic level ratio referenced to digital full level (7FFFH / 8000H).
RMS unweighted: Root Mean Square measurement without special weighting filter, measures flat within 22 Hz to 22 kHz.
Sample frequency: Number of samples taken from the analog signal per second.
Word length: Same as bit resolution. Number of bits per sample. 16-Bit: 65536 steps or 96 dB dynamic range
