Grace Digital M201 - Manual (Page 11)

grace design m201
owner’s manual
11
all the available sampling rates. Simply push the button to select the sampling
rate you require. The selected rate will be illuminated green below. Selecting “OFF”
puts the A/D converter circuitry in low power standby mode with all oscillators off.
CLOCK SOURCE The m201 A/D can be run from the internal crystal, an external word
clock source, or from DigidesignTM loopsync*. The top middle switch, labeled CLOCK
SOURCE, is used to select between these options. The selected clock source will be il-
luminated green below the switch.
A/D MODE The m201 A/D is capable of transmitting AES/EBU digital audio in sin-
gle or dual wire modes, and in either professional or consumer format. The upper left
switch selects between these various formats. The selected format will be illuminated
green below the switch.
PEAK RESET / MODE High resolution 20 segment metering is included with the
m201 A/D option. When A/D input signals hit or exceed absolute zero (0dBfs), the over
indicator lights (‘over’ placed above and below ‘0’ on the meter) will illuminate red and
remain lit until the peak reset switch is pushed.
Peak signal levels are indicated by the highest level LED remaining lit. The peak in-
dicators can programmed to remain lit indefinitely until the reset switch is pressed
(infinite); stay lit for 4 seconds (delay); or not stay lit at all (off ). These three modes are
selected by simply pressing and holding the PEAK RESET / MODE switch for approxi-
mately 3 seconds, which toggles through the three available modes.
A/D Converter Sensitivity
The m201 A/D converter features two independent A/D sensitivity configurations. The
front panel interface allows the user to easily switch between these two calibrated set-
tings. Each of the two input sensitivity ranges (A) and (B) can be configured for one of
four standard A/D sensitivities. The following sections detail the operation and calibra-
tion of this feature.
SELECTING THE A/D SENSITIVITY From the m201 front panel interface, pressing
and releasing the INPUT SENS push button toggles the selected A/D input sensitivity.
The currently selected range (A) or (B) is illuminated.
CALIBRATING THE A/D SENSITIVITY The m201 ships with the following two de-
fault sensitivity calibrations: (A)+22dBu = 0dBFS (18dB Headroom) (B)+18dBu =
0dBFS (14dB Headroom). Internal trim controls allow you to reconfigure either (or
both) of the sensitivity levels. Four standard sensitivities are supported in the m201
A/D converter: +18dBu = 0dBFS (14dB Headroom) +20dBu = 0dBFS (16dB Headroom)
+22dBu = 0dBFS (18dB Headroom) +24dBu = 0dBFS (20dB Headroom).