Installation manual

Hardware installation2–51
24 bit (factory set – default)
This setting, which is the default, passes all 24 bits of input sample data to the digital signal processing stages that
follow. This setting should be used when all data presented to the DAB has between 16 and 24 bits of significant
information and there are no auxiliary data or intercom channels used in the AES/EBU bit stream.
Note: If auxiliary data is present, it will cause increased noise or distortion in the audio data as the DAB
cannot differentiate between auxiliary data and actual audio sample data.
V Bit Ignore/Enable
The AES/EBU data stream contains a bit called the data “Valid” bit for each audio sample. This bit can be used to show
a damaged sample, or that the data is invalid for one reason or another. Normal operation for the DAB is to ignore this
bit and use any audio sample data that is present. However, the DAB can be configured to use the “V” bit to mute all
audio samples that arrive. When set for “Enable,” normal audio will pass unless the “V” bit is set. If the V bit indicates
invalid audio sample data, all bits in the data will be set to zeros before being passed to the digital signal processing sec-
tions. The factory default is to ignore the “V” bit.
Internal Sine Generator
The DAB 3500/4000 and DEX 3500 have a test jumper that puts the DSP in a debug mode. This mode puts a 1 kHz tone
on the outputs regardless of the data that is on the inputs. This is used for factory test.