Lectrosonics UT Block 28 mit VMS Super-Nieren Kapsel (Vorführgerät)
The UT Digital Hybrid WirelessTM* handheld transmitter uses state-of-the-art wireless technology with a unique microphone capsule arrangement. The VariMicTM 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 VariMicTM preamp.
In addition to providing peerless audio quality in native 400 Series mode, the Digital Hybrid WirelessTM tech nology 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 informa tion in digital form, at the cost of some combination of power, bandwidth and resistance to interference.
UT Block Diagram
The Lectrosonics Digital Hybrid WirelessTM 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 bene ts of conventional FM wireless systems, such as excellent range, ef cient use of RF spectrum, and long battery life. However, unlike con ventional 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 con verter 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.
The transmitter was designed to operate with Lectro sonics Digital Hybrid WirelessTM receivers and will yield the best performance when doing so. However, due to the exibility 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 bene t 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 transmit ters in a system have different pilot tone frequencies so that even spurious RF from the wrong transmitters can’t open the receiver squelch.
The ±75 kHz deviation dramatically improves the cap ture ratio, signal to noise ratio and dynamic range of a wireless system.
A digitally-controlled limiter and a precise, 16-position attenuation control allow a very wide range of gain set tings 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 alka line 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.
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 in terference problems in mobile or traveling applications.
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 ve feet. It also provides additional RF output stage protection but is rarely seen in a wireless micro phone transmitters due to the considerable expense.
The highly ef cient 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 con guration. This allows the mic to be held in any position, since the user’s hands have little or no effect on the radiated power.
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 suspen sions in order to eliminate handling noise. Each capsule is also mated with the unique VariMicTM preamp ar rangement allowing for custom-tailoring the frequency response based on application.
*Digital Hybrid Wireless® is a patented design that combines 24-bit digital audio with an analog FM radio link to provide outstanding audio quality and the extended operating range of the finest analog wireless systems.
The design overcomes channel noise in a dramatically different 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. Instead, it is a technique which can be accomplished only in the digital domain, even though the audio inputs and outputs are analog signals.
*US Patent 7,225,135