Lectronics Digital Hybrid Wireless HHa-941, Инструкция по эксплуатации

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Wideband Hand Held Transmitter
Rio Rancho, NM
5
Pilot Tone Squelch
The benefit of the pilot tone squelch system is that the
associated receiver will remain muted until it receives
the pilot tone from the matching transmitter, even if a
strong RF signal is present on the carrier frequency of
the system. Digital Hybrid Wireless
®
transmitters use
one of up to 256 different ultrasonic tones between 25
and 32 kHz in each standard frequency to operate the
receiver squelch.
The pilot tone frequency is determined by the selected
operating frequency in 100 kHz steps. The same pilot
tone is used for all four frequencies within each 100
kHz step of the tuning range.
Input Gain Range and Limiter
45 dB range of input gain adjustment allows gain
settings to accurately match the user’s voice and the
varying sensitivity of different microphone capsules. A
DSP-controlled analog audio limiter is employed be-
fore the A-D converter. The limiter has a range of more
than 30 dB for excellent overload protection. A dual re-
lease envelope makes the limiter acoustically transpar-
ent while maintaining low distortion. It can be thought
of as two limiters in series, a fast attack and release
limiter followed by a slow attack and release limiter.
The limiter recovers quickly from brief transients, with
no audible side effects, and also recovers slowly from
sustained high levels to keep audio distortion low while
preserving short term dynamics.
Long Battery Life
Switching power supplies throughout the design al-
low over 5 hours of operation using two alkaline AA
batteries. The battery compartment and contacts are
designed to prevent “rattle” as the unit is handled.
Menu-Driven Control
A high-resolution LCD and control panel with mem-
brane switches provide access to the menu-driven
setup. Transmitter RF power, high-pass filter, frequency
selection, backlight timeout, mute or talkback functions
and tuning modes are easily accessed.
Frequency Selection
Operating frequency is normally selected using a
receiver or analyzer to assess signals in the local en-
vironment to avoid interference. Once an interference-
free frequency is identified, the transmitter frequency is
set to match the receiver.
The LCD on the transmitter displays frequency in MHz
and with a two character hex code.
Antenna
A uniquely designed helical antenna allows the trans-
mitter to be held in any position, since the user’s hands
have little or no effect on the RF output power.
Microphone Capsules
The transmitter is available from Lectrosonics with
the HHC and HHVMC cardioid condenser capsules.
Capsules from several other manufacturers are also
available for use with the HH: those with a 1.25” x 28
thread pitch and three contact rings. Condenser or
dynamic microphone heads can be used with the HH,
depending on the user’s preference or the application.
IR (infrared) Sync
An IR Sync Port is used for quick setup with receivers
that offer this feature. Settings for frequency, step size
and compatibility mode are transferred from receiver to
transmitter via the IR ports.
Side Button Functions
A programmable switch on the side of the housing can
be configured as a mute/cough switch, to provide a
talkback function, a power switch, or be disabled.
The talkback function provides a communication
channel when used with a receiver equipped with this
feature. When pressed and held in, the side switch re-
directs the audio output to a different audio channel on
the receiver. As soon as the switch is released, audio
is returned to the program channel.
The talkback function works only in the Digital Hybrid
compatibility mode.
USB Port for Firmware Updates
Firmware updates are enabled by simply downloading
a file and utility program from the Lectrosonics web
site, connecting the transmitter to a computer via the
USB port and running the program.