Digitally driven combination coils for electrodynamic acoustic transducers
First Claim
1. In combination with an acoustical transducer having at least two independently addressable coils, a modulator and amplifier comprising means for converting an analog input signal to pulse width modulated signals and amplified output means for addressing the signals to respective ones of said coils.
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Accused Products
Abstract
An electrodynamic acoustic transducer (54) having two voice coils (50, 52), the coils being addressed by amplified digital signals. The system (12, 60, 54) utilizes a preamplified analog input signal (10) which is supplied to a bifurcated network, one such signal being processed by an inverter (18). The analog signals (42, 44) are compared with triangular waves (38, 40) to effect switched signals (46, 48) that are pulse width modulated signals. The signals (46, 48) are then amplified through impedances (76, 78) and high speed, high current semiconductor switch means (80, 82) so that the amplified digital signals serve as driver means communicated to the separately addressable coilds (50, 52). There is a dynamic balance achieved by separate energization of the coils (50, 52) whereby the diaphragm (97) is positively located in both axial driving directions and is disposed in equilibrium positions by the energization and balancing of the respective coils (50, 52). As a result, the dynamic range, clarity, cleaness, and response time is substantially improved. An important aspect of this invention is the direct addressing of two distinct coils (50, 52) by amplified pulse trains which are of digital characteristic. The speaker (54) does not require mechanical restoring means but instead the suspension of the diaphragm (97) has a high compliance and serves only to maintain concentric relationship of the voice coils (50, 52) with the gap (92).
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Citations
15 Claims
- 1. In combination with an acoustical transducer having at least two independently addressable coils, a modulator and amplifier comprising means for converting an analog input signal to pulse width modulated signals and amplified output means for addressing the signals to respective ones of said coils.
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8. An acoustical transducer system comprising a modulator means for converting preamplified analog input signals to modulated switched signals, a means for amplifying the output of the modulating means, and a dual coil acoustical transducer means having independently addressable coils for receiving respective signals of the amplified modulated output.
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9. A process for transducing electrical signals to an acoustical output of an electrodynamic acoustic transducer comprising the steps of applying a preamplified analog signal to a switched converting means, converting the preamplified analog signal input through said switched converting means to effect conversion of the analog signal to pulse width modulated switched signals, amplifying the output of the converting means, and communicating the amplified switched signals to selected ones of addressable coils whereby the switched signals generate a driving force effecting an acoustical output.
- 10. A process for converting an electrical signal to an acoustic signal through an electrodynamic acoustic transducer comprising the steps of generating an analog signal, communicating such signal to a pulse width modulated signal transformation means, communicating the output in amplified form to said acoustic transducer, and separately addressing each of two coils with the amplified output to effect said acoustic signal.
Specification