Pacific Microsonics HDCD Model Two - Multichannel Slave Operation and Analog Recording

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INC.

PACIFIC MICROSONICS

Setup & Operation

Model Two HDCD

User’s Manual

Rev. C - January 2002

For AD Operating Modes Multichannel “Slave”:

1. From the Operating Menu, select the desired Base Sample Rate (SETUP/MODE/44.1_X

or 48_X) and Preset Configuration (SETUP/PRESETS).

2. From the Operating Menu, select (SETUP/INPUT/REFCLK/REFWCLK).

3. From the Operating Menu, select (SETUP/INPUT/MON_REF/A/D_REF).

For DD Operating Modes Multichannel “Slave”:

1. From the Operating Menu, select the desired Base Sample Rate (SETUP/MODE/44.1_X

or 48_X) and Preset Configuration (SETUP/PRESETS).

2. From the Operating Menu, select (SETUP/INPUT/REF_CLK/REFWCLK).

In 2X and 4X sampling rate AD and DD operating modes, the reference clock frequency can

be set to 1X or 2X. From the Operating Menu, select (SETUP/INPUT/REF_FRQ/1X_REF or

2X_REF). NOTE: If a 2X reference clock is used when a 1X input or output data rate is

selected, there can be an output phase ambiguity between multiple Model Twos locked

to the same clock. All factory presets have a default 1X clock frequency.

NOTE: The Model Two’s word clock output is a floating signal with positive and negative

voltage potentials. This is done to avoid ground loops between multiple Model Twos used

for multichannel A/D conversion. The floating signal is compatible with most CMOS “TTL

compatible” 75 Ω word clock inputs found on modern equipment. A “true” TTL clock input

will draw more current, which may reduce the signal amplitude to below safe TTL trigger

levels. An AC coupled CMOS input word clock distribution amplifier with a ground refer-

enced TTL compatible output can be used to buffer the signal if necessary.

Recording From an Analog Source

When performing 24-bit or 20-bit A/D conversion, setting peak signal levels within 2 dB of

full scale is sufficient. Since the Model Two’s 24-bit or 20-bit resolution is so much greater

than 16-bit, it is not necessary to risk signal “overs” by pushing the level to full scale.

Peak signal levels can be transparently increased later using DSP Gain.

A warm up time of at least 30 minutes is recommended prior to A/D conversion or critical

D/A monitoring. The Model Two should be set to an A/D mode during warm up, which

exercises the A/D converters with dither. A/D conversion can be clocked by either the

Model Two’s internal clock or an external reference.

Setup for 44.1/48 kHz, 88.2/96 kHz or 176.4/192 kHz A to D Conversion

In all A/D Modes, the Model Two converts analog signals into HDCD 24-bit, 20-bit, or 16-

bit signals. Either 44.1 kHz or 48 kHz clock families are selected in the 44.1/48 Base Rate

Sample Rate Menu (SETUP/MODE/44.1_X or 48_X).