Digital Hybrid Wireless Belt-Pack Transmitters
Rio Rancho, NM
3
and robustly as possible, yielding audio performance
that rivals that of purely digital systems, without the
power, noise and bandwidth problems inherent in digital
transmission. Because it uses an analog FM link, Digital
Hybrid Wireless
enjoys all the benefits of conventional
FM wireless systems, such as excellent range, efficient
use of RF spectrum, and long battery life.
Servo Bias Input and Wiring
The input preamp is a unique design that delivers
audible improvements over conventional transmitter
inputs. Two different microphone wiring schemes are
available to simplify and standardize the configuration.
Simplified 2-wire and 3-wire configurations provide sev-
eral arrangements designed for use only with servo bias
inputs to take full advantage of the preamp circuitry.
A line level input wiring provides an extended frequency
response with an LF roll-off at 35 Hz for use with instru-
ments and line level signal sources.
DSP-controlled Input Limiter
The transmitter employs a digitally-controlled analog
audio limiter prior to the analog-to-digital converter.
The limiter has a range greater than 30 dB for excellent
overload protection. A dual release envelope makes the
limiter acoustically transparent while maintaining low
distortion. It can be thought of as two limiters in series,
connected as a fast attack and release limiter followed
by a slow attack and release limiter. The limiter recovers
quickly from brief transients, so that its action is hidden
from the listener, but recovers slowly from sustained
high levels to keep audio distortion low and preserve
short term dynamic changes in the audio.
Recorder function
The SMWB has a built in recording function for use in
situations where RF may not be possible or to work as
a stand alone recorder. The record function and trans-
mit functions are exclusive of each other - you cannot
record AND transmit at the same time. When the unit is
transmitting and recording is turned on, the audio in the
RF transmission will stop, but the battery status will still
be sent to the receiver.
The recorder samples at 44.1kHz rate with a 24 bit
sample depth. (the rate was selected due to the re-
quired 44.1kHz rate used for the digital hybrid algo-
rithm). The micro SDHC card also offers easy firmware
update capabilities without the need for a USB cable or
driver issues.
Compatibility with
microSDHC memory cards
Please note that the SMWB and SMDWB are designed
for use with
microSDHC memory cards
. There are
several types of SD card standards (as of this writing)
based on capacity (storage in GB).
SDSC
: standard capacity, up to and including 2 GB –
DO NOT USE!
SDHC
: high capacity, more than 2 GB and up to and
including 32 GB –
USE THIS TYPE
.
SDXC
: extended capacity, more than 32 GB and up to
and including 2 TB –
DO NOT USE!
SDUC
: extended capacity, more than 2TB and up to
and including 128 TB –
DO NOT USE!
The larger XC and UC cards use a different formatting
method and bus structure and are NOT compatible with
the recorder. These are typically used with later genera-
tion video systems and cameras for image applications
(video and high resolution, high speed photography).
ONLY microSDHC memory cards should be used. They
are available in capacities from 4GB to 32GB. Look for
the Speed Class 10 cards (as indicated by a C wrapped
around the number 10), or the UHS Speed Class I
cards (as indicated by the numeral 1 inside a U sym-
bol). Also note the
microSDHC
Logo.
If you are switching to a new brand or source of card,
we always suggest testing first before using the card on
a critical application.
The following markings will appear on compatible
memory cards. One or all of the markings will appear on
the card housing and the packaging.
UHS Speed Class I
Stand-alone
Speed Class 10
UHS Speed Class 1
UHS Speed Class I
Accompanying
microSDHC logo
microSDHC Logo is a trademark of SD-3C, LLC
