Lectrosonics IFBT4 Frequency-Agile Compact Transmitter, (Frequency Block 24) 614.40-639.90MHz

The Lectrosonics IFBT4 transmitter was designed for use in broadcast, motion picture, theater and stage applications where extended operating range and high quality audio are essential. The transmitter can be used as a stand-alone device or patched directly into popular intercom systems. Lectrosonics Digital Hybrid Wireless U.S. Patent 7,225,135 systems overcome 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 that can be accomplished only in the digital domain, even though the inputs and outputs are analog. 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 resistance to interference. However, unlike conventional FM systems, it does away with the analog compandor and its artifacts. 256 UHF frequencies in 100kHz steps provide exceptional flexibility in coordinating frequencies in multi-channel wireless systems and avoiding interference from external RF signal sources and noise.

Microprocessor control provides user-friendly operation and eliminates transients at turn-on and turn-off. The transmitter output is muted in the TUNE mode to avoid generating interference in other wireless systems while scrolling up and down to change frequencies. In the XMIT mod e, the output is turned on and the frequency cannot be changed. The transmitter delivers 250 mW of output power which, when used with an efficient antenna, provides exceptional operating range with the R1A belt-pack receiver. Indoors, the signal will penetrate various surfaces and reflect from others efficiently to extend operating range and reduce the need for critical antenna positioning.

A supersonic pilot tone signal controls the audio squelch on the R1A receiver to eliminate noise when the transmitter is turned off and it prevents the receiver from locking onto false signals. The pilot tone also eliminates noise in the receiver at turn-on and turn-off. The LCD display is backlit for use in dimly lit conditions and is also highly visible in direct sunlight. DIP switch settings on the rear panel provide direct compatibility with RTS and Clear Com intercom systems. A preamp stage is also included in the input stage to allow direct connection to dynamic microphones in "standalone" applications.

Direct output at studio line level can also be fed directly into the transmitter. The transmitter housing is rugged, machined aluminum with an electrostatic powder coating and an anodized finish. The unit is powered by 6 to 18 Volts DC via a locking connector. The supplied whip antenna is a detachable, locking 1/4 wavelength flexible, galvanized steel cable that connects to a 50 Ohm BNC connector on the rear panel.