The human brain is able to decipher the movements of the tympanic membrane, that is, it is able to perceive sounds. Sound is simply the overlapping of pressure waves which travel through the air (sound does not travel in a vacuum) and reach the ear.
In the case of an audio application, an electronic signal made up of a series of data which, once decoded by the reader, amplified by the chain of preamplifier and amplifier, and filtered to eliminate possible disturbances, adequately adapted and transferred, determine movements in the membranes of acustic transductors (loudspeakers, subwoofers etc), which are then sent through the air in the form of pressure waves to reach the ear, where they are decodified by the brain in the form of sound.
Of course all the manipulations modify the electronic signal, introducing distortions which are important to a greater or lesser degree. This can be seen above all by carrying out Fourier’s analysis of the signal itself; the whole electronic signal elaborated by the application (which will result in music) is simply the overlapping of numerous electromagnetic waves of different intensity and frequency. By separating the different waves that form the signal, all the components can be evidenced as shown in the diagram.
The introduction of distortions in the signal, that is, the addition of spurious waves that overlap the signal, are, as described before, components at different frequencies which contribute to forming the signal but they are not part of the initial codification and therefore they alter the resulting signal. In practice the sound has an annoying background of rustling, buzzing and other noises.
From all this we can deduce the importance of an audio application having an resisting adapter or a transformer designed for audio distribution which introduces the lowest possible number of disturbances so that the signal codified on the magnetic support can be faithfully reproduced by acustic transductors.
With the specific purpose of satisfying these requirements, TECA has introduced a series of transformers that elaborate the signal without introducing significant distortions within the bandwidth, even in the presence of a high number of harmonics.
These transformers are designed with the customer so as to make the product perfectly suitable for the application. It is possible to fully satisfy the real needs of the customer, keeping under control the costs which are determined by the dimensions and the materials as well as the final characteristics of the transformer.
The customer’s requirements determine the mechanical characteristics (dimensions), electrical characteristics (power, voltage and current), applicative characteristics (cut-off frequency, attenuation tolerance) and installation characteristics (length and colour of the wires, contacts and connectors, and method of fixing the transformer).
The figures which usually characterise transformers for audio distribution are a bandwidth between 100Hz and 18KHz, input voltages with values of 50-70-100V and output resistances of 4-8-16 Ohms. The planning and production of the transformers in this series require particular attention to detail so as to guarantee practically perfect linearity for the whole bandwidth, within which it is possible to have maximum oscillations of 0.5dB and a reduction in the signal to 3dB, far beyond (10 times) the upper cut-off frequency.
The testing of the product’s quality is particularly careful, as in the case of audio supply transformers. Thus every stage from planning to despatch is fully tested in every respect: electronic, magnetic and safety.