IFBT4-VHF
LECTROSONICS, INC.
6
the Main window navigates to the Frequency window.
The Frequency window displays the current operating
frequency in MHz, as well as the standard Lectrosonics
hex code. Also displayed is the UHF television channel to
which the selected frequency belongs.
In XMIT mode, it is not possible to change the operating
frequency.
In TUNE mode, the Up and Down buttons may be used
to select a new frequency.
The UP and DOWN buttons navigate in 175 kHz incre-
ments. Holding the MENU butto+Up and MENU+Down
move 2.8 MHz at a time. In any of the various group tun-
ing modes, the currently selected group identifier is dis-
played to the left of the hex code, and the Up and Down
buttons navigate among the frequencies in the group.
In factory group tuning modes A thru D, MENU+Up and
MENU+Down jump to the highest and lowest frequen-
cies in the group. In user group tuning modes U and V,
MENU+Up and MENU+Down permit access to frequen-
cies not currently in the group.
Pressing and holding the Up or Down button invokes an
autorepeat function, for faster tuning.
Audio Input Gain Window
Pressing the MENU button once from
the Frequency window navigates to
the Audio Input Gain window. This
window greatly resembles the Main
window, with the exception that the current audio input
gain setting is displayed in the upper left corner. The Up
and Down buttons may be used to alter the setting while
reading the realtime audio meter to determine what
setting works best.
The gain range is -18 dB to +24 dB with 0 dB nominal
center. The reference for this control can be changed with
the rear panel MODE switches. See the
Installation and
Operation
section for more information on the MODE
switches.
Setup Window
Pressing the MENU button once
from the Audio Input Gain window
navigates to the Setup window. This
window provides access to a menu
for various setup screens.
Initially the active menu item is EXIT. Pressing the Up
and Down keys permits navigation to the menu items:
COMPAT and ROLLOFF.
Pressing the MENU button selects the current menu
item. Selecting EXIT navigates back to the Main window.
Selecting any other item navigates to the associated setup
screen.
ROLLOFF Setup Screen
The ROLLOFF setup screen controls
the low frequency audio response of
the IFBT4 by moving the 3 dB corner
IFBT4 Front Panel
OFF/TUNE/XMIT Switch
OFF Turns the unit off.
TUNE Allows all functions of the transmitter to be set
up, without transmitting. The operating frequen-
cy may only be selected in this mode.
XMIT Normal operating position. The operating
frequency may not be changed in this mode,
though other settings may be changed, so long
as the unit isn’t “Locked.”
Power Up Sequence
When power is first turned on, the front panel LCD
display steps through the following sequence.
1.
Displays Model and the firmware verson
(e.g. IFBT4VHF and V1.0).
2.
Displays the current compatibility mode setting
(e.g. COMPAT IFB).
3.
Displays the Main Window.
Main Window
The Main window is dominated by an
audio level meter, which displays the
current audio modulation level in real
time. In TUNE mode, a blinking
capital “T” is displayed in the lower left corner to
remind the user that the unit is not yet transmitting. In
XMIT mode, the blinking “T” is replaced by an antenna
icon.
Audio limiting is indicated when the audio bargraph
extends all the way to the right and widens somewhat.
Clipping is indicated when the zero in the lower right
corner changes to a capital “C”.
The Up and Down buttons are disabled in this Window.
Frequency Window
Pressing the MENU button once from
Front Panel Controls and Functions
