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FM-531HD / May 2013
G E N E R A L I N F O R M A T I O N
Basic Setup
Once the processor is rack mounted and connected to a clean source of AC power
it is ready for operation. Basic setup and adjustment may be accomplished using the
front panel and adjustments to the input and output and preset takes may be made. To
tailor the sound of a preset, the GUI interface running on a Windows PC will be needed.
The setup procedure that follows uses the front panel controls.
• Connect the Analog or Digital audio inputs as appropriate for your installation.
• Select the main input source (Analog or Digital). Digital may be via XLR AES
or optional WheatNet‑IP.
• While in the <INPUT> menu and observing the Input meters, adjust the Input Gain
control (Digital or Analog as appropriate) until the input meters are
just peaking at
-12dBFS with normal program levels coming from the studio or program source.
Setting input levels correctly is an important step towards getting the best audio
performance from the FM-531HD audio processor. Note that the input meters
are sample-accurate and include peak (dot) over average (bar) displays, and it is
normal to see the average levels reading quite low (perhaps below -20dBFS) when
feeding the processor with unprocessed audio.
• For best overall audio chain performance, the Input of the FM-531HD should be
calibrated so that it reaches 0dBFS when the signal chain prior to the processor
reaches its 0dBFS, or digital full scale level. This aligns the overload point of the
audio chain prior to the processor for maximum headroom and best signal to noise.
• Set the Pre-Emphasis to the value that is appropriate for your region.
Note that
if pre-emphasis has been enabled in the Input menu all FM outputs will be pre-
emphasized unless De-Emphasis for that output is explicitly selected.
• Now make the audio output connections appropriate for your installation, noting
that the Analog and Digital outputs may be used simultaneously.
• The FM-531HD is shipped with the analog output set for MPX. This means that
the two BNC female connectors (TX-1 and TX-2) plus the analog XLR connec
‑
tors (Left or Right) may be used for composite operation. To use these outputs in
other modes (L/R or L/R de-emphasized) you must connect to the processor using
the supplied GUI on a Windows PC. Adjust the TX outputs as needed for 100%
modulation. This should be done with normal programming and not test tones.
The RMS level of alignment tones does not crest at 100%. It may take a minute
or so with minor adjustments to find a good starting point based on the music/
speech programming being fed to the processor. The default setting is +2.40dB
and is calibrated this way to drive the default levels on most exciters.
• If using the AES Digital Output, connect it to the equipment following the
FM-531HD and adjust the AES Output level control in the Output Menu as ap
‑
propriate for your installation.
• If using the digital baseband192 output, modulation levels into the exciter are
controlled by the TX-1 and TX-2 level controls. Currently only the TX-1 signal
is supported by transmitter manufacturers.
• The FM-531HD Audio Processor factory default preset is called Quick Start.
We recommend using this preset as a starting point for aligning and putting the
processor on the air. Once the processor is actually on the air, you may scroll thru
the list of presets to find one that best represents the format of the station. To do
Summary of Contents for FM-531 HD
Page 2: ...Technical Manual Wheatstone Corporation May 2013 FM HD Digital Audio Processor FM 531hd...
Page 122: ...page A 2 FM 531HD May 2013 A P P E N D I C E S Appendix A General Specifications A 3 Contents...
Page 128: ...page A 8 FM 531HD May 2013 A P P E N D I C E S Appendix B FM 531HD GPI Interface A 9 Contents...
