page 2 – 3
AM-55 / Sep 2015
F R O N T P A N E L
Limiter Meters
There are five limiter meters for the multiband limiter, plus one more for the final
limiter. These meters only have a 14dB scale since limiters do much less work on the
audio than the AGC section does. Please see Chapter 3 on the multiband limiter for a
deeper explanation on its operation and tuning.
Output Meters
There are two sets of output meters, each with two bargraph columns.
One pair of the output meters shows the upper 42dB of the AM‑55’s 144dB internal
dynamic range and indicate the digital peak output level in dBFS at output of the AM‑55’s
final peak limiting, not the audio level at the output connectors.
Note that the levels for the analog and digital outputs are adjusted by the same pair
of TX1 and TX2 level controls.
The other pair of output meter columns show the extent of positive and negative going
modulation levels as they are being generated by the AM‑55’s processing.
OLED Display
On the front panel of the AM‑55 is an OLED display that allows you to set up,
configure and place the processor on the air with a preset without having to set up the
GUI interface. You can also make adjustments to the audio and set up user access to the
front panel from this screen.
Adjustments are simple. The knob
navigates up and down a menu when
there is a list, or scrolls through options
in a submenu once one has been selected.
Pushing the knob “takes” an option, while
the “W” (WheatNet‑IP) button backs out
of a submenu to the main menu.
The main menu of the AM‑55 shows all of the options available from the front panel.
These options are:
•
Headphone
– Selects the headphone source and volume level.
•
Presets
– Selects a user or factory preset to place on the air.
•
Input
– Selects the input mode (Analog, Digital AES or Digital
WheatNet‑IP) and sets the gain structure for the analog and digital
modes.
•
Pre-Emphasis
– Sets the pre‑emphasis used, depending on your
region and application. The options are FLAT, 50us, and NRSC.
