Abstract: In signal sources having a high impedance, typically a capacitive “signal source” such as capacitor-microphone capsules, it is common practice to use amplifier circuits that include means for coupling signals and determining operating points in addition to the actual amplifier having a high-resistance, non-inverting input. For setting the operating points of the signal source and the amplifier, separate bias-voltage sources are provided; these are coupled to the signal source and the non-inverting input, respectively, of the amplifier via a coupling impedance. At least one coupling capacitance is disposed in the signal path between the signal source and the non-inverting input of the amplifier. To attain a considerable noise gain without the disadvantage of very high idle times in this type of amplifier circuit, it is proposed that the coupling impedances be formed from a nonlinear resistance (D1, D2 or D3, D4) and an ohmic resistance (R3 or R4) connected thereto in series.

Abstract: In signal sources having a high impedance, typically a capacitive “signal source” such as capacitor-microphone capsules, it is common practice to use amplifier circuits that include means for coupling signals and determining operating points in addition to the actual amplifier having a high-resistance, non-inverting input. For setting the operating points of the signal source and the amplifier, separate bias-voltage sources are provided; these are coupled to the signal source and the non-inverting input, respectively, of the amplifier via a coupling impedance. At least one coupling capacitance is disposed in the signal path between the signal source and the non-inverting input of the amplifier. To attain a considerable noise gain without the disadvantage of very high idle times in this type of amplifier circuit, it is proposed that the coupling impedances be formed from a nonlinear resistance (D1, D2 or D3, D4) and an ohmic resistance (R3 or R4) connected thereto in series.

Abstract: With a method for converting an analog input signal (S1) to a digital output signal (S7), the analog input signal (S1) is amplified in a first signal path (2, 3, 5) and is subjected to an analog-to-digital conversion (5). In a second signal path (4, 6), another analog signal (S4) is obtained for transmitting larger signal amplitudes and is subjected to an analog-to-digital conversion (6). The signal (S5) digitized in the first signal path (2, 3, 5) and the signal (S6) that is digitized in the second signal path (4, 6) are fed to a digital signal processor (7), which generates the digital output signal (S7). To avoid an abrupt reduction in the signal resolution and achieve the highest possible dynamic scope, it is suggested that the analog signal fed to the second signal path (4, 5) be distorted non-linear and counter to the amplified analog signal (S2) in the first signal path (2, 3, 5).

Abstract: To facilitate direct conversion to digital form of an acoustic signal acting on the acoustic receptor of an acoustic receiver while satisfying requirements of dynamic range, noise and adequate quantization, the following is proposed: the acoustic receptor should be exposed to a counter-signal when the acoustic signal acts on it in such a way that the acoustic receptor is largely maintained in its rest state despite the action of the acoustic signal. The counter-signal is derived from the control variable of a control circuit which is a component of the acoustic receptor. The control variable contains the information on the acting acoustic signal. Any deviation of the receptor from its rest state immediately generates a digital “nought” or “one.

Abstract: The invention relates to a balanced circuit arrangement for converting an asymmetric analogous input signal (S1) into a symmetrical output signal (S2, S3). A first amplifier (2) is provided, whereby the non-inverting input thereof is connected to the analogous input signal (S1) and the output signal (S2) thereof is fed back to the inverting input thereof in a negative feedback. Moreover, a second amplifier (3) is provided, whereby the non-inverting input thereof is connected to ground, the inverting input thereof is connected to the output signal (S2) of the first amplifier (2) by means of a series resistor (R2) and the output signal (S3) thereof is fed back to the inverting input thereof in a negative feedback and by means of a negative feedback resistor (R1). The negative feedback resistor (R1) and the series resistor (R2) are provided with the same resistance value. The aim of the invention is to process higher maximum levels of the source signal and to suppress noises of the second amplifier.

Abstract: An electroacoustic transducer system comprises a microphone working into a low-frequency amplifier for the energization of an a-c load such as, for example, a loudspeaker or a volume indicator at a control panel. Biasing voltage for the microphone and operating current for the amplifier are derived from a d-c source, via a phantom circuit including the output leads of the amplifier and through a coupler in cascade with a chopper; the latter includes a transistor conducting intermittently under the control of an adjustable pulse generator whose pulse width is varied by negative feedback from the integrated chopper output. An output transformer with a primary in series with the transistor has several secondaries each connected across a storage capacitor through a diode for the generation of a relatively high biasing voltage for the microphone, a relatively low driving voltage for the amplifier and, possibly, a further voltage used to vary the directional pattern of the microphone.

Abstract: A system for controlling the mean depth and spacing of V-grooves cut by a stylus in a phonograph disk for recording stereophonic sounds comprises a processing stage deriving first and second signal components, designed for the vertical and lateral deflection of a stylus support, from advanced left and right preview signals picked up from a storage medium about half a disk revolution ahead of the actual modulation signals.