1. Introduction
Welcome
Congratulations, and thank you for purchasing the Digital Audio Denmark ADDA2402 audio
converter. You have in your possession an extremely capable audio converter, which enables
you to perform high-end analog-to-digital, digital-to-analog and digital-to-digital conversion
of audio signals.
Overview of ADDA 2402
The ADDA2402 is a full duplex converter, which can perform independent simultaneous
analog-to-digital (A/D), and digital-to-analog (D/A) conversion between analog audio signals
and AES/EBU or S/PDIF digital audio signals. The digital interfaces comply to AES3
1
.
The A/D converter converts an analog audio signal to a high quality digital signal with a
sample-rate of 32 kHz, 44,1 kHz 48 kHz, 64 kHz, 88,2 kHz or 96 kHz, a noise floor below
117 dB(A)
2
at 44,1 Khz sampling, and a THD+N below 107 dB at 6 dBu input level.
The input level can be monitored on the Peak Programme Meter (PPM) at the front, and the
input can be selected to be either the XLR connectors or Jack connectors.
The A/D conversion is 24 bit. Depending on the conversion application the A/D converter
resolution can be reduced to 20 bit, 18 bit or 16 bit by adding psycho acoustic dither
3
to the
signal.
The bandwidth of the converted signal is equal to half the sample-rate, giving a bandwidth
from 16 to 48 kHz. The filters in the A/D converter assure that no signal is present above half
the sample-rate. This means that no aliasing distortion is introduced in the A/D converter.
Having no alias components in the digital signal eliminates the risk of generation of Alias
Intermodulation Distortion (AID)
4
.
The D/A converter converts a digital audio signal to a high quality analog signal having a
dynamic range better than 117 dB(A) at 44,1 Khz sampling, and a THD+N below 90 dB at
6 dBu output level.
You can chose between three digital input sources, either a professional AES/EBU signal on
XLR connectors, a consumer S/PDIF signal on Phone connectors or an optical S/PDIF signal
on a TosLink connector.
The D/A converter automatically adapts to the sample-rate of the incoming digital signal
which can be 32 kHz, 44,1 kHz 48 kHz, 64 kHz, 88,2 kHz or 96 kHz.
The ADDA 2402 can also be configured as a digital-to-digital (D/D) converter for sample-rate
conversion (SRC) of a digital input of a given sample-rate and format to a digital output of an
other sample-rate and format.
The converter can do sample-rate conversion between any of the six sample-rates from 32
kHz, 44,1 kHz 48 kHz, 64 kHz, 88,2 kHz to 96 kHz, and convert between the professional
and the consumer AES/EBU format.
ADDA 2402 has high precision internal oscillators with a stability of +/- 5 parts per million
(PPM) controlling the sample-rates. The ADDA2402 can also be synchronised to an external
reference signal complying with AES 11
5
.
1
Please refer to section 5, references for an explanation of AES 3.
Please refer to section 3, The peak meter for a description of the input levels and the dB
notification.
3
Please refer to section 5, references for an explanation of the psycho acoustic dither.
4
Please refer to Appendix 1 for a description of AID.
5
Please refer to section 5, references for an explanation of AES 11.
7
