Lectrosonics UT400 User Manual
UT
Synthesized UHF Hand-Held Transmitter
INSTRUCTION MANUAL
Featuring Digital Hybrid Wireless® Technology*
*US Patent 7,225,135
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Rio Rancho, NM, USA
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UT
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LECTROSONICS, INC.
Synthesized UHF Hand-Held Transmitter
Table of Contents
General Technical Description ..............................................................................................................................................................4
Introduction ...........................................................................................................................................................................................4
Digital Hybrid Technology .....................................................................................................................................................................4
Digital Signal Processor........................................................................................................................................................................ 4
Microprocessor, PLL and VCO Circuits.................................................................................................................................................4
Compatibility Modes..............................................................................................................................................................................5
Pilot Tone Squelch ................................................................................................................................................................................5
Wide-Band Deviation ............................................................................................................................................................................5
Input Limiter ..........................................................................................................................................................................................5
Long Battery Life................................................................................................................................................................................... 5
Frequency Selection .............................................................................................................................................................................5
Circulator/Isolator.................................................................................................................................................................................. 5
Antenna.................................................................................................................................................................................................5
Microphone Element.............................................................................................................................................................................5
Controls and Functions .........................................................................................................................................................................6
Power On/Off Switch.............................................................................................................................................................................6
Power LED ............................................................................................................................................................................................6
Compatibility Modes..............................................................................................................................................................................6
Frequency Switches..............................................................................................................................................................................6
Audio Level LEDs..................................................................................................................................................................................7
Audio Level Control...............................................................................................................................................................................7
Locked Mode ........................................................................................................................................................................................7
VariMic™ Controls..................................................................................................................................................................................8
Bass/Mid/Treble (LO/MID/HI) ................................................................................................................................................................8
Preamp Level Control ...........................................................................................................................................................................8
Subsonic Noise Filter............................................................................................................................................................................9
Interchangeable Capsules ....................................................................................................................................................................9
Changing Capsules..............................................................................................................................................................................10
Operating Instructions.........................................................................................................................................................................12
Selecting Compatibility Mode..............................................................................................................................................................12
Adjusting the Audio Gain ....................................................................................................................................................................12
Power ON/OFF Switch Function Selection .........................................................................................................................................13
Battery Installation ...............................................................................................................................................................................14
Operating Notes....................................................................................................................................................................................15
Adjusting the Transmitter Frequency...................................................................................................................................................15
Troubleshooting....................................................................................................................................................................................16
Specifications .......................................................................................................................................................................................17
Service and Repair ...............................................................................................................................................................................18
Returning Units for Repair ..................................................................................................................................................................18
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General Technical Description
Introduction
The UT Digital Hybrid Wireless™ handheld transmitter
uses state-of-the-art wireless technology with a highpowered 100mW RF output and a unique microphone
capsule arrangement. The VariMic™ preamp allows the
user to custom-tailor the microphone’s response to suit
the application.
Three capsules are available for this transmitter: a cardioid condenser, an omni condenser and a super-cardioid
condenser. Each capsule assembly comes complete
with the VariMic™ preamp.
In addition to providing peerless audio quality in native
400 Series mode, the Digital Hybrid Wireless™ technology in the UT transmitter allows compatibility with a
wide range of receiver types, including Lectrosonics 100
and 200 series and IFB. The UT is also compatible with
receivers from other manufacturers. Contact Lectrosonics for details.
Digital Hybrid Technology
All wireless links suffer from channel noise to some
degree and all wireless microphone systems seek to
minimize the impact of that noise on the desired signal. Conventional analog systems use compandors for
enhanced dynamic range, at the cost of subtle artifacts
(known as “pumping” and “breathing”). Wholly digital
systems defeat the noise by sending the audio information in digital form, at the cost of some combination of
power, bandwidth and resistance to interference.
The Lectrosonics Digital Hybrid Wireless™ system
(hereafter called Digital Hybrid) overcomes channel
noise in a dramatically new way, digitally encoding the
audio in the transmitter and decoding it in the receiver,
yet still sending the encoded information via an analog
FM wireless link. This proprietary algorithm is not a
digital implementation of an analog compandor but a
technique which can be accomplished only in the digital
domain, even though the inputs and outputs are analog
signals.
Because it uses an analog FM link, the Digital Hybrid
enjoys all the benefits of conventional FM wireless
systems, such as excellent range, efficient use of RF
spectrum, and long battery life. However, unlike conventional FM systems, the Digital Hybrid has done away
with the analog compandor and its artifacts.
Digital Signal Processor
The DSP encodes the digitized audio from the A-D converter and adds an ultrasonic pilot tone to control the
receiver’s squelch (only in 400 Series, 200 Series and
IFB compatibility modes with the pilot tone enabled –
see Pilot Tone Squelch). It also controls the input limiter
and audio metering.
Microprocessor, PLL and VCO Circuits
An 8-bit microprocessor monitors numerous internal
signals. It also drives the Modulation LEDs, controls the
pilot tone and operates the PLL/VCO circuits.
UT Block Diagram
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LECTROSONICS, INC.
Synthesized UHF Hand-Held Transmitter
Compatibility Modes
The transmitter was designed to operate with Lectrosonics Digital Hybrid Wireless™ receivers and will yield
the best performance when doing so. However, due to
the flexibility of digital signal processing, it is also able
to operate with Lectrosonics 200 Series, Lectrosonics
100 Series, IFB and certain non-Lectrosonics analog
receivers in special compatibility modes. (Contact the
Lectrosonics Sales Department for a complete list of
compatible receivers.)
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. All 400 Series transmitters use one
of 256 different ultrasonic tones between 25 and 32
kHz to modulate the carrier to operate the receiver
squelch. The pilot tone frequency is chosen according
to which of the 256 channels has been selected by the
frequency switch setting. This ensures that all transmitters in a system have different pilot tone frequencies so
that even spurious RF from the wrong transmitters can’t
open the receiver squelch.
Wide-Band Deviation
The ±75 kHz deviation dramatically improves the capture ratio, signal to noise ratio and dynamic range of a
wireless system.
Circulator/Isolator
The RF output circuit includes a one way circulator/
isolator using magnetically polarized ferrite. This device
greatly reduces RF intermodulation produced when
multiple transmitters are used at separations of less
than five feet. It also provides additional RF output
stage protection but is rarely seen in a wireless microphone transmitters due to the considerable expense.
Antenna
The highly efficient antenna uses the lower half of the
printed circuit boards as one radiating element, with the
upper half of the PC boards and the mic capsule as the
other half of the dipole configuration. This allows the mic
to be held in any position, since the user’s hands have
little or no effect on the radiated power.
Microphone Element
The UT handheld transmitter is available with any of
three capsule types: the VMC cardioid condenser, the
VMO omni condenser and the VMS super-cardioid
condenser. All three are mounted with tuned suspensions in order to eliminate handling noise. Each capsule
is also mated with the unique VariMic™ preamp arrangement allowing for custom-tailoring the frequency
response based on application.
Input Limiter
A digitally-controlled limiter and a precise, 16-position
attenuation control allow a very wide range of gain settings based on the source volume, thus optimizing the
signal-to-noise performance in any situation. The result
is the widest dynamic range of any wireless condenser
microphone today.
Long Battery Life
Switching power supplies throughout the design allow
over 3.5 hours of operation using a single 9 VDC alkaline battery. (A 9 VDC lithium battery will provide over
6.5 hours of operation.) The battery contacts are spring
loaded to prevent “rattle” as the unit is handled.
Frequency Selection
The transmitter section uses a synthesized, frequency
selectable main oscillator. The frequency is extremely
stable over a wide temperature range and over time.
Two 16-position rotary switches, located under the
battery door, provide 256 frequencies in 100 kHz steps
over a 26.5 MHz range. This alleviates most carrier interference problems in mobile or traveling applications.
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Controls and Functions
Power On/Off Switch
A Power On/Off switch located on the outside bottom
of the unit turns the unit on and off. The function of the
Power On/Off Switch can also be changed so it also
operates as an audio mute switch. In this configuration,
the Power LED doubles as a battery status indicator (in
the unmute or On position) and an audio mute/unmute
indicator (in the muted or Off position). (See Operating
Instructions, Power Switch Function Selection.) These
functions are illustrated in the chart below:
If the UT Power On/Off Switch has been configured
for Audio Mute Mode, it is still possible to turn off the
transmitter without removing the battery. This is done
by placing the switch in the On position, then toggling
the switch between the On and Off position three times
in less than five seconds, i.e., On (Starting Position)Off-On-Off-On-Off.
The user-selected configuration of the Power On/Off
switch is stored in the unit’s memory and persists until
reconfigured by the user.
Function On Off
Normal, or Applies Power Turns Unit Off
Power Mode to Unit
Audio Mute Enables Audio Mutes Audio
Power Switch Position
Mode
Power LED
Whether in normal, mute or locked mode, the Power
LED will indicate the battery level when the unit is powered up.
The Power LED
indicates the battery
status when the unit
is powered up with
the Power On/Off
switch configured for
normal operation.
The Power LED
glows green when
the battery is good.
The color changes
to red when there
is about 30 minutes
of operation left with the recommended lithium battery.
(An alkaline battery will have about 20 minutes of life
left.) When the LED begins to blink red, there are only
a few minutes of life left in the battery. The Power LED
blinks red for a short period when the transmitter is configured for Normal Mode and the Power On/Off switch
is set to Off. At the end of the power off sequence, then
Power LED goes out.
Power LED
Power On/Off
Switch
Battery
Compartment
Cover
NOTE: A NiMH battery gives little or no warning
when it is depleted. If you use NiMH batteries
in the UT, we recommend trying fully charged
batteries first, noting the length of time that the
batteries will run the unit and in the future use
somewhat less than that time to determine when
the battery needs to be replaced.
When first tinstalled, a weak battery will sometimes
cause the Power LED to glow green, but will soon discharge to the point where the LED will blink red or shut
off completely.
When Power On/Off switch is configured for Audio Mute
Mode, the Power LED indicates battery status when the
switch is set to On. However, when the Power On/Off
swtich is configured for Audio Mute Mode and set to Off,
the Power LED will slowly double blink green to indicate
that the unit’s audio is muted. (See Operating Instruc-
tions, Power Switch Function Selection.)
Compatibility Modes
The Power LED is used to indicate Compatibility Mode.
To identify the current Compatibility Mode, as part of the
powerup sequence, the Power LED will blink:
• Once for 100 Series mode
• Two times for 200 Series mode
• Three times for Mode 3*
• Four times for 400 Series mode
• Five times for IFB Series mode
*This mode works with analog receivers from other
manufacturers. Contact Lectrosonics for a complete list
of non-Lectrosonics compatible receivers.
Windscreen
Audio Level Control
Power LED
Power On/Off Switch
Modulation
Level LEDs
Frequency
Switches
Battery
Compartment
Locking ring
(Open Position)
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LECTROSONICS, INC.
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