Lectrosonics Announces LecNet2 Firmware Update For DMTH4 Telephone Hybrid

Improved algorithms yield increased functionality

DMTH4 and LecNet2. Firmware UpdateRio Rancho, NM… Lectrosonics, recognized the world over as a leading manufacturer of wireless microphone systems and audio processing products, is pleased to announce Version 2.0 of the LecNet2 firmware for the DMTH4 telephone hybrid interface. Incorporating a series of improved algorithms utilized in the DMTH4’s acoustic and line echo cancellers, the new update promises greater functionality in a number of key areas, including dynamic convergence factor control, convergence regardless of system Echo Return Loss (ERL), improved metering accuracy, a more robust line echo canceller, and a “Boa Constrictor” algorithm that prevents divergence.

The new algorithm in the V2.0 firmware adjusts the DMTH4’s convergence factor automatically, eliminating the compromise imposed by a fixed convergence factor. The process accurately and reliably measures residual echo content in the far side transmission signal. When the content is high, the convergence factor is increased to facilitate faster convergence, and when the content is low, the convergence slows down to achieve greater depth of echo cancellation. A manual adjustment is also provided in the control panel GUI (graphical user interface) for more precise fine tuning.

The improved echo canceller in the V2.0 firmware will converge even with a negative Echo Return Loss (ERL) in systems where the far side returns more echo level than the original signal. The algorithm uses a direct measurement of residual echo content in the far side transmission signal—based upon mutual information in the actual receive and send signals as opposed to being controlled by near/far levels. Because of the variable convergence factor, the echo canceller functions as a ‘boa constrictor’ and takes advantage of even very brief pauses in speech to converge at a fast rate and, as a result, continually makes small improvements—thus yielding impressive echo cancellation depth.

The line echo canceller also benefits from the V2.0 improvements since it utilizes the same algorithms as the acoustic echo canceller. The line echo canceller is very tolerant of even gross mismatches in the termination impedance of the telephone line.

Implementing the new firmware requires no hardware modifications. The firmware can be downloaded and installed into existing DMTH4 processors. V2.0 firmware will ship with all DMTH4 processors starting in June 2007 and will also be available for download from the Lectrosonics web site (www.lectrosonics.com).

About Lectrosonics

Well respected within the film, broadcast, and theater technical communities since 1971, Lectrosonics wireless microphone systems and audio processing products are used daily in mission-critical applications by audio engineers familiar with the company's dedication to quality, customer service, and innovation. Lectrosonics is a US manufacturer based in Rio Rancho, New Mexico.