Optimod-AM 9400 V1.2 Operating Manual - Orban
Optimod-AM 9400 V1.2 Operating Manual - Orban
Optimod-AM 9400 V1.2 Operating Manual - Orban
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OPTIMOD-<strong>AM</strong> DIGITAL TECHNICAL DATA 6-9<br />
3. Digital Input Receiver and Sample Rate Converter (SRC)<br />
Located on Input/Output board<br />
The integrated receiver and input sample rate converter, IC500, accepts digital<br />
audio signals using the AES3 interface format (AES3-1992). The built-in sample<br />
rate converter (SRC) accepts and sample-rate converts any of the “standard” 32<br />
kHz, 44.1 kHz, 48 kHz, 88.2 kHz, and 96 kHz rates in addition to any digital audio<br />
sample rate within the range of 32 kHz and 96 kHz. The SRC converts the input<br />
sample rate to 64 kHz. The final, high-quality decimation to the <strong>9400</strong> system<br />
sample rate is done in the system DSP, as was done for the analog input.<br />
This chip is surface-mounted and not field-replaceable.<br />
Output Circuits<br />
The <strong>9400</strong> has two stereo pairs of analog outputs and two AES3 digital outputs. We<br />
will describe Output #1; Output #2 is identical except for its component reference<br />
designators.<br />
This circuitry interfaces the DSP to the analog and digital audio outputs. The digital<br />
audio from the DSP is transmitted to the digital-to-analog converter (D/A) or output<br />
sample rate converter (SRC) associated with a given output. The digital-to-analog<br />
(D/A) converter converts the digital audio words generated by the DSP to analog<br />
audio. The analog output stages scale and buffer the D/A output signal to drive the<br />
analog output XLR connectors with a low impedance balanced output. The digital<br />
output transmitter accepts the digital audio words from the output sample rate<br />
converter (SRC) and transmits them to the digital output connector via an AES3 output<br />
formatter and driver chip.<br />
1. Stereo Digital-to-Analog (D/A) Converter<br />
Located on input/output board<br />
The D/A, IC211, is a stereo, 24-bit delta-sigma converter. It receives the serial left<br />
and right audio data samples from the DSP at 64 kHz sample rate, and converts<br />
them into audio signals requiring further, relatively undemanding analog filtering.<br />
IC211 is surface-mounted and is not field-replaceable.<br />
2. Analog Output Stages<br />
Located on Input/Output board<br />
The left and right analog signals emerging from IC211 are each filtered, amplified,<br />
and applied to a floating-balanced integrated line driver, which has a 50<br />
output impedance. The line driver outputs are applied to the RF-filtered left and<br />
right analog output connectors. These analog signals can represent either the<br />
transmitter or monitor output of audio processing.<br />
Component-Level Description:<br />
IC201 and associated components filter the left channel signal emerging from