1. Functionality (cont’d.)
1-3. VU / PPM Meter
The VU/PPM meters are 3 color LED bar displays, with 53 segments per channel.
By using a core DSP processor, all of the monitoring for the four (two stereo) signal channels are
processed in the digital domain for both RMS and PPM and calculated in real-time.
The VU and PPM values are then displayed in the range from –34 dBu ( -53 dBFS ) to +18 dBu ( 0
dBFS ) in 1 dB increments. All Analog signals are converted to the digital domain before being
processed by the DSP.
1-4. Out-of-Phase and Silence Monitoring
Out-of-Phase and Continuous Silence conditions for the selected audio sources are indicated by
the PHASE and A or B switch LEDs respectively. When an Out-of-Phase condition occurs on
monitor source A, the PHASE LED illuminates and the A switch flashes for the duration of the
condition.
A period of silence on a selected channel will illuminate the SILENCE LED for the duration of the
condition. The time period required to constitute a silence condition is selectable using the user-
preset DIP switches to be either 5 or 10 seconds. The Sensitivity threshold is adjustable to either –
36 dBFS or –48 dBFS.
1-5. Line output
Two stereo Analog line outputs, and optionally, two AES3 Digital outputs are provided. Digital line
outputs are mirror images of the Analog line outputs. The stereo source signals for the VU/PPM
meters are routed to these line outputs.
1-6. User presets
The internal user-preset DIP switch is located at the left-hand side near the power supply circuitry
on the main circuit board, and is designated as SW600. The eight switches provided for user-
presets are to define Silence duration, Silence threshold level, and Test tone mode.
Test tones with 0 VU (-18 dBFS) levels and frequencies of 400 Hz and 1 kHz can be generated
and routed to both the A and B line outputs when the TEST-TONE user preset switch is turned on.
The Silence duration and threshold level are both adjustable with the user preset switch for
convenience.
USER PRESET SWITCHES
1 ~ 5 Undefined
6 Test Tone
Off No test tone
On -18 dBFS , 400 Hz test tone routed to both A and B left output
channels, and 1 kHz test tone routed to both A and B right output channels.
7 Silence threshold level
On -36 dBFS
Off -48 dBFS
8 Silence duration
Off 10 seconds
On 5 seconds