DE430216C - Arrangement for damping the natural vibrations of membranes for telephones, microphones, gramophones and similar devices - Google Patents

Description

GERMAN EMPIRE

ISSUED JUNE 11, 926

REICH PATENT OFFICE

PATENT LETTERING

- JVl 430216 - CLASS 21 a2 GROUP 13

(Sch 70507 VIII \ 2icP)

· Hermann Schunck in Munich.

Arrangement for damping the natural vibrations of membranes for telephones, Microphones, gramophones and similar apparatus.

Patented in the German Empire on May 16, 1924. -

With many elastic ones. Systems, e.g. B. membranes of telephones, microphones and. Gramophones, the natural vibrations work of the system very annoying. It is therefore necessary to have a relatively strong damping (e.g. by applying a strong membrane) to apply the natural vibrations to suppress. This is associated with a loss of energy, which z. B. on the phone expresses that the broadcast

Sound energy nmr represents a certain fraction of the electrical energy absorbed, while the rest by the necessary to suppress the natural oscillation Attenuation of the membrane is transformed into heat.

The present invention avoids this drawback by using a selective one Damping of the natural oscillation, so that an ίο elastic system arises, which in relation to the natural oscillation is strongly damped, on the other hand with respect to the forced oscillation is undamped or weakly damped.

The selective damping can extend to one or more natural oscillation frequencies, depending on. one or more frequencies natural oscillations of the ¹ elastic system should be suppressed.

The selective attenuation can be based on median or by electrical means, in particular it can be used for telephone, microphone or gramophone membranes are made by the adjusting arrangement (see illustration) :

α is the membrane, b the telephone magnet (or, in the case of a microphone, the sound pen), c a control magnet which transmits the vibrations of the membrane to an electrical system consisting of the capacitor d and the coil e . The coil e transmits the oscillation to an oscillating circuit, which consists of the coil / and the capacitor g and is tuned to the natural oscillation of the membrane α. It is applied to the grid and cathode of the electron tube h . In the anoderic circuit is the magnet I, which has the damping effect on the membrane in that the oscillations of the magnet / are in phase opposition with those of the magnet c due to a suitable winding direction of the coils e and / as well as a suitable choice of the capacitor d. Since the oscillation circuit / g is only triggered by the coil e during the natural oscillation of the diaphragm β, the damping has a selective effect.

Claims (2)

Patent-to sayings: i. Arrangement for damping the natural vibrations of membranes for telephone, Microphones, gramophones and similar apparatus, characterized by the affixing of one to one or more Natural vibration frequencies of the diaphragm matched selective damping for the purpose of a with respect to forced Vibrations undamped or weakly damped elastic system with no or only weak natural vibrations ■ received. 2. Arrangement according to claim i, characterized in that the movements of the Diaphragm in the windings of an electromagnet (c) cause current changes, which in turn have a three-electrode tube (controlling oscillation ski) that is tuned to the natural frequency of the membrane ('/ g ·) affect in the resonance case, and that in the starting circle of the Tube an electromagnet (/) which acts back on the membrane and is in phase opposition works with the magnet (c).