Abstract: Disclosed boost amplifiers are used with a BTL amplifier that outputs balanced audio signals and that has an output current capacity and a dynamic power capacity. Disclosed amplifiers include an audio amplifier with a dynamic power capacity and that amplifies the balanced audio signals and applies them to a load, at least one diode that receives audio signals and produces single-ended input power signals, and at least one regulator that converts the single-ended input power signal into a regulated power signal of a higher magnitude. The boost regulator presenting a variable input impedance to the BTL amplifier such that the output current capacity of the BTL amplifier is not exceeded. Disclosed amplifiers also include a DC power reservoir that stores power from the regulated power signal and supplies sufficient power that the dynamic output power capacity of the audio amplifier exceeds the dynamic power capacity of the BTL amplifier.

Abstract: Disclosed loudspeakers include a frame, a magnetic yolk affixed to the frame, a voicecoil, a spider, a resilient surround, and a cone. The yoke includes a slotted sidewall and a central slug that form an air-gap. The voicecoil is disposed within the gap and includes a former, with top and bottom edges, and at least one winding. The voicecoil moves when receiving alternating electrical potentials. The spider has a flexible portion, has rigid members extending through the yolk slots, and has a channel affixed to the former bottom edge such that the channel is no wider than the former and winding(s). The cone includes an inner portion affixed to the former top edge and an outer portion affixed to the frame through the surround, wherein the inner portion includes rigid members capable of movement within the sidewall slots with movement of the voicecoil. Optionally, the former has apertures therethrough.

Abstract: Disclosed loudspeakers include a frame, a magnetic yolk affixed to the frame, a voicecoil, a spider, a resilient surround, and a cone. The yoke includes a slotted sidewall and a central slug that form an air-gap. The voicecoil is within the gap and includes a former, with top and bottom edges, and at least one winding on the former. The voicecoil moves when receiving alternating electrical potentials. The spider has a flexible outer portion, has an inner portion with rigid members that always extend through the yolk slots, and is affixed to the former bottom edge. The cone includes an inner portion affixed to the former top edge and an outer portion affixed to the frame through the surround, wherein the inner portion includes rigid members capable of movement within the sidewall slots with movement of the voicecoil.

Abstract: Methods and apparatus for audio signal clip detection are disclosed. The clip detectors may receive audio signals, from which peak reference signals, indicative of the highest voltage of the received audio signals, may be derived. The received audio signals may also be differentiated and phase-lagged to produce differentiated audio signals which may, in turn, be rectified to produce rectified differentiator signals. The rectified differentiator signals and the peak reference signals may be compared to thereby produce clip detect signals indicative of whether the received audio signals are clipped. The clip detect signals may then be used to indicate whether the received audio signal are clipped.

Abstract: An amplifier device including an amplifier having an input for receiving an audio input signal and an output for sending an output signal to a load. A boosted-rail circuit is connected to a power source and has a single boosted rail connected to the BTL amplifier. Also, a common-mode circuit is coupled to the boosted-rail circuit and the BTL amplifier. The common-mode circuit sends a common-mode signal to the BTL amplifier that will dynamically track the output voltage supplied from the boosted-rail circuit to the BTL amplifier. In operation, the boosted-rail circuit reacts to the BTL amplifier and switches from a non-boost mode to a boost mode to increase the output voltage supplied to the BTL when the BTL amplifier requires additional voltage.

Abstract: A switching amplifier including a voltage sensor circuit connected to a high voltage supply rail for measuring the power supply voltage. A current sensor circuit is connected to the high voltage supply rail for measuring the power supply current. An error amplifier is connected to the switching amplifier and receives one or more values based on the measurements taken by the voltage sensor and current sensor, and the error amplifier produces an error signal when a predetermined power limit is exceeded. A signal limiting circuit is connected to the error amplifier and the switching amplifier and limits the output power to rated power at any rated load impedance when the error amplifier produces the error signal. This switching amplifier is capable of automatically limiting output power at rated power into all rated load impedances, and dynamically reacts to the frequency-dependant impedance of a typical audio system.

Abstract: A switching amplifier including a voltage sensor circuit connected to a high voltage supply rail for measuring the power supply voltage. A current sensor circuit is connected to the high voltage supply rail for measuring the power supply current. An error amplifier is connected to the switching amplifier and receives one or more values based on the measurements taken by the voltage sensor and current sensor, and the error amplifier produces an error signal when a predetermined power limit is exceeded. A signal limiting circuit is connected to the error amplifier and the switching amplifier and limits the output power to rated power at any rated load impedance when the error amplifier produces the error signal. This switching amplifier is capable of automatically limiting output power at rated power into all rated load impedances, and dynamically reacts to the frequency-dependant impedance of a typical audio system.

Abstract: A switching amplifier including a voltage sensor circuit connected to a high voltage supply rail for measuring the power supply voltage. A current sensor circuit is connected to the high voltage supply rail for measuring the power supply current. An error amplifier is connected to the switching amplifier and receives one or more values based on the measurements taken by the voltage sensor and current sensor, and the error amplifier produces an error signal when a predetermined power limit is exceeded. A signal limiting circuit is connected to the error amplifier and the switching amplifier and limits the output power to rated power at any rated load impedance when the error amplifier produces the error signal. This switching amplifier is capable of automatically limiting output power at rated power into all rated load impedances, and dynamically reacts to the frequency-dependant impedance of a typical audio system.

Abstract: An amplifier device including an amplifier having an input for receiving an audio input signal and an output for sending an output signal to a load. A boosted-rail circuit is connected to a power source and has a single boosted rail connected to the BTL amplifier. Also, a common-mode circuit is coupled to the boosted-rail circuit and the BTL amplifier. The common-mode circuit sends a common-mode signal to the BTL amplifier that will dynamically track the output voltage supplied from the boosted-rail circuit to the BTL amplifier. In operation, the boosted-rail circuit reacts to the BTL amplifier and switches from a non-boost mode to a boost mode to increase the output voltage supplied to the BTL when the BTL amplifier requires additional voltage.

Abstract: An improved Class BD amplifier provides an amplified output signal by pulse width modulation techniques by sampling a carrier wave, usually a triangular or saw tooth waveform, according to an input signal to be amplified, as in a conventional class D amplifier. The resulting sampling waveform controls the connectivity of the potential supplies 34, 36 to the power rails 14, 18 via the first switch 12 so that a first potential and a second potential are alternately supplied to the first power rail 14 and so that a third potential and fourth potential are alternately supplied to the second power rail 18. As shown in FIG. 8, the first potential is positive, the second and third potentials are at ground, and the fourth potential is negative. In addition, a constant potential difference is maintained between the first and second power rails 14, 18. The power rails are alternately connected to a Class AD output stage 26 by another switch 30, the connectivity of which is controlled by a second sampling waveform, PWM.

Abstract: An amplifier providing the linear output of a Class A amplifier and the expanded peak current output and efficiency of a Class AB amplifier. The amplifier includes an input amplifier, a voltage regulator network, a cascode stage, and an output amplifier. The input amplifier amplifies a signal current into two outputs. The cascode stage and the output stage each contain two paths for the amplified outputs. The voltage regulator network interconnects the two paths between the input amplifier and the cascode stage. The voltage regulator network bypasses a high percentage of the quiescent current that is normally contained in the two paths of the cascode stage and the output amplifier stage, thus improving the peak-to-quiescent current output ratio beyond the 2:1 value of traditional Class A amplifiers.

Abstract: An audio amplifier, particularly suited for automotive applications, providing improved isolation between the preamplifier section and the power amplifier section. The preamplifier section ground is isolated from the power amplifier section ground. The amplifier includes a voltage regulator with output feedback for supplying a regulated voltage to the preamplifier section. The voltage regulator is referenced to the preamplifier section ground.

Abstract: An amplifier providing the linear output of a Class A amplifier and the expanded peak current output and efficiency of a Class AB amplifier. The amplifier includes an input amplifier, a voltage regulator network, a cascode stage, and an output amplifier. The input amplifier amplifies a signal current into two outputs. The cascode stage and the output stage each contain two paths for the amplified outputs. The voltage regulator network interconnects the two paths between the input amplifier and the cascode stage. The voltage regulator network bypasses a high percentage of the quiescent current that is normally contained in the two paths of the cascode stage and the output amplifier stage, thus improving the peak-to-quiescent current output ratio beyond the 2:1 value of traditional Class A amplifiers.

Abstract: Tree pole ladder which includes first and second detachable sections. Each of the detachable sections pivotally supports laterally extending steps which the foldable from a horizontally extending position for climbing, to a storage position aligned with the pole section. The detachable sections are coupled together by a coupling section which permits the sections to be rapidly connected and detached to a pair of single pole sections which may be easily transported to remote locations.

Abstract: The specification discloses an audio signal level control system including a center-tapped photocell incorporated into an attenuator bridge. The cell elements are monitored while processing the audio signal, and a control circuit regulates the light-emitting device in the cell in response to the monitored bridge values. Preferably, log compression and filtering are performed within the control means. Also preferably, a tracking subtraction principle is used in both the audio and control paths to expand the control dynamic range.

Abstract: An amplifier topology suitable for amplification of the frequency dependent output of a transducer to provide a frequency equalized amplifier output includes a first transconductive stage for converting a voltage input signal to the current domain through a signal node and a second transreactive stage for converting the signal current into an output voltage. An active equalization network feeds back a representation of the output signal to the signal node in such a way that the fed back signal voltage error is not affected by the high impedance thereat to provide error correction feedback that is achromatic with frequency and, accordingly, does not vary across the range of frequencies amplified, to provide the second amplifier with a frequency independent closure ratio, while not reducing second amplifier voltage gain.

Abstract: A distortion-free amplifier in accordance with the present invention includes an input amplifier, an output amplifier and method, and a cooperative combination of negative and positive feedback loops that remove substantially all distortion and error in the amplified output. Negative feedback loops are provided around the output amplifier and the input/output amplifier combination to provide degenerative error reduction. The negative feedback loop around the output stage provides a portion of the output to a voltage node at which the error component of the output signal is inversely superposed on the inverted signal to be amplified. This highly "visible" (inverse, intra-loop) error component is utilized as positive feedback to provide a regeneratively enhanced error pre-correction of the signal in the input amplifier. The pre-correction can be precisely controlled to effect virtually complete serial cancellation of the to-be-introduced error as the signal is propagated through the amplifier.

Abstract: An amplifier for a capacitive load which includes a pair of high-voltage tube output circuits connected in a power output tube arrangement operating in push-pull for driving a capacitive load together with a feedback network connected between the Schmitt arrangement and a pair of transistors interconnected in a complementary difference amplifier circuit, the output of the complementary difference amplifier circuit connected to the driving tube of the power output tube arrangement to provide an amplifier output level having low distortion, positive DC centering and a high order of stability.

Abstract: An audio step-up circuit for driving an electrostatic loudspeaker of full-range-element configuration from a low voltage, low impedance, audio signal source utilizes two specially designed audio transformers in parallel-bilateral interconnection including R-C networks, one transformer being designed for optimum spectral response in the region of 30 Hz to about 5 kHz, and the other transformer being designed with cooperative added input impedance means for optimum spectral response in the region from a few hundred Hz to 20 kHz in such manner as to achieve an equalized-pass characteristic complementary to the loudspeaker therethrough in the audio range, while at the same time affording resonant conservation of energy at high frequencies.

Abstract: An improved Class BD amplifier provides an amplified output signal by pulse width modulation techniques by sampling a carrier wave, usually a triangular or saw tooth waveform, according to an input signal to be amplified, as in a conventional class D amplifier. The resulting sampling waveform controls the connectivity of the potential supplies 34, 36 to the power rails 14, 18 via the first switch 12 so that a first potential and a second potential are alternately supplied to the first power rail 14 and so that a third potential and fourth potential are alternately supplied to the second power rail 18. As shown in FIG. 8, the first potential is positive, the second and third potentials are at ground, and the fourth potential is negative. In addition, a constant potential difference is maintained between the first and second power rails 14, 18.