Abstract: In a speaker system, pulse width modulation signals are utilized for driving said speaker system, and duty cycles of both left audio channel signals and right audio channel signals of an earphone in said speaker system are modulated by said pulse width modulation signals. When the left audio channel or the right audio channel of the earphone has no inputted audio signals with the abovementioned modulated duty cycles, the speaker system may be prevented from unnecessary power consumption. Besides, audio signals from both the left audio channel and the right audio channel of the earphone and outputted from the speaker system may thus be synchronized further by both the pulse width modulation signals and a sawtooth wave source for generating said pulse width modulation signals, for reducing noise and increasing an output audio quality of the speaker system. The abovementioned speaker system is preferably utilized for a Class D amplifier.

Abstract: The invention discloses a class-D amplifier, which is used for driving a two-terminal load according to a set of analog signals. The D-class amplifier includes a pulse-width modulation (PWM) circuit, a signal processing circuit and a driving amplifier circuit. The PWM circuit receives the set of analog signals and converts them into a set of PWM signals with identical phase. The signal processing circuit generates a set of pulse signals which are attached to the set of PWM signals respectively. The driving amplifier circuit is coupled between the signal processing circuit and the two-terminal load. The driving amplifier circuit receives and amplifies the set of PWM signals. According to the set of PWM signals, the driving amplification circuit drives the two-terminal in a filterless way.

Abstract: A class D amplifier including a PWM circuit, a buffer amplifying circuit, a low-pass filter, and two current sources is provided. The PWM circuit transfers an analog signal into a PWM signal. The buffer amplifying circuit amplifies the PMW signal and generates an amplified signal. The low-pass filter will filter high frequency components out from the amplified signal and then transmit the filtered signal to a loading of the class D amplifier. The two current sources provide currents flowing into and out from a feedback node in the PWM circuit, respectively. The charging and discharging provided by the two current sources can generate a triangular signal for the PWM circuit.

Abstract: An audio playback apparatus is disclosed. The audio playback apparatus processes an audio signal and provides at least one output signal to at least one speaker or an earphone connected to a phone-jack. The audio playback apparatus comprises a clock generating module, a processing module, an amplifier module, and a detecting module. The processing module is connected to the clock generating module and processes the audio signal to generate a processed signal according to a clock signal generated by the clock generating module. The amplifier module amplifies the processed signal to generate an output signal. The detecting module detects whether the earphone is plugged in the phone-jack. If the earphone is plugged in the phone-jack, the amplifier module provides the output signal to the earphone. If not, the amplifier module provides the output signal to the speaker.

Abstract: An audio signal processing apparatus is provided. The audio signal processing apparatus comprises a clock generator, a processing module, an amplifying module and an output module. The clock generator is used for generating a clock signal. The processing module is coupled to the clock generator for processing the clock signal and generating a processing signal. The amplifying module is coupled to the processing module for amplifying the processing signal and generating an amplifying signal. The output module is coupled to the amplifying module for outputting the amplifying signal.

Abstract: The invention relates to a crossover exercise recumbent bike, comprising a pedal mechanism positioned on the bike body with a seat provided thereon. The characteristic of the invention lies in that each of two pedal cranks thereof has an axis of rotation tilted forward to form an included angle between the transversal direction; accordingly, when an exerciser steps on pedals to rotate the two cranks, the invention enables the exerciser to promote the multiple efficacy of exercise of firming up lower body (legs and butt) and strengthening upper body (flat abs) at the same time.

Abstract: After coupling a first voltage source to a voltage supply circuit, a second voltage source having a same electrical level but an opposite electrical pole with said first voltage source is generated. An audio amplifier is then driven by both the first voltage source and the second voltage source, where said audio amplifier requires a pair of voltage sources having the same electrical level but opposite electrical poles to be driven. The voltage supply circuit generates the second voltage source from the first voltage source by simultaneously switching two sets of switches, where said both sets of switches have non-synchronous statuses in switching.

Abstract: In a speaker system, pulse width modulation signals are utilized for driving said speaker system, and duty cycles of both left audio channel signals and right audio channel signals of an earphone in said speaker system are modulated by said pulse width modulation signals. When the left audio channel or the right audio channel of the earphone has no inputted audio signals with the abovementioned modulated duty cycles, the speaker system may be prevented from unnecessary power consumption. Besides, audio signals from both the left audio channel and the right audio channel of the earphone and outputted from the speaker system may thus be synchronized further by both the pulse width modulation signals and a sawtooth wave source for generating said pulse width modulation signals, for reducing noise and increasing an output audio quality of the speaker system. The abovementioned speaker system is preferably utilized for a Class D amplifier.

Abstract: After coupling a first voltage source to a voltage supply circuit, a second voltage source having a same electrical level but an opposite electrical pole with said first voltage source is generated. An audio amplifier is then driven by both the first voltage source and the second voltage source, where said audio amplifier requires a pair of voltage sources having the same electrical level but opposite electrical poles to be driven. The voltage supply circuit generates the second voltage source from the first voltage source by simultaneously switching two sets of switches, where said both sets of switches have non-synchronous statuses in switching.

Abstract: An audio amplifier includes a plurality of sub-audio amplifier sets, a clock source, and a speaker. When the audio amplifier is under an audio amplify mode, the plurality of sub-audio amplifier sets is operated under a synchronic operating frequency with a same clock signal generated by the clock source. When the audio amplifier is under a self-oscillation mode, the clock signal is isolated from being input to the plurality of sub-audio amplifier sets. A higher distortion is prevented by repeatedly charging and discharging an oscillating capacitor of a sub-audio amplifier in a sub-audio amplifier set.

Abstract: The present invention provides an asynchronous BTL (Bridge Tied Load) design for a Class-D audio amplifier. The Class-D audio amplifier comprises two independent signal routes, each of the two independent signal routes includes a PWM (Pulse Width Modulator), a predriver and a power MOS circuit; each of the two independent signal routes receives an input signal via the PWM thereof, and outputs signal through the power MOS circuit thereof, and then cooperatively drive a loudspeaker; no synchronous signal is inputted to each of the two PWMs, and the two power MOS circuits feed back independent signals respectively to the two PWMs. The present invention omits the synchronous design of the prior art, and let the two push-pull signals required by the BTL design being processed independently, while cooperatively drive the loudspeaker.

Abstract: A self oscillation system capable of eliminating interference is provided. The self oscillation system comprises a plurality of channel oscillation circuits and a plurality of eliminators. The plurality of channel oscillation circuits generates a plurality of channel oscillation signals according to a plurality of channel input signals. The plurality of eliminators respectively coupled to two of the plurality of channel oscillation circuits eliminates cross talk.

Abstract: A designed shell for Christmas ornamental ball having a plurality of linear ribs formed integral with the inside wall thereof subject to a predetermined design and separating the inside wall into a plurality of recessed spaces and a beyond-design area, the recessed spaces being surrounded by the linear ribs and respectively colored with light-penetrable color paints to show the predetermined design.

Abstract: A detachable Christmas ornamental ball includes a light penetrable spherical shell having an opening, and a cap-like top cover detachably fastened to the opening of the spherical shell to hold at least one lamp socket and a lamp bulb on each lamp socket in the spherical shell, the top cover having a peripheral wall defining a bottom open chamber, two springy hook plates formed integral with the peripheral wall at two opposite sides and respectively hooked on the periphery of the opening of the spherical shell to secure the top cover to the spherical shell, a plurality of splits cut through the peripheral wall at two opposite lateral sides of each of the springy hook plates, and two springy oblique retaining plates suspended in the bottom open chamber and adapted to hold at least one lamp socket in the spherical shell.

Abstract: A detachable Christmas ornamental ball includes a light penetrable spherical shell having an opening sufficient for the insertion of a C-type lamp bulb, and a cap-like top cover detachably fastened to the opening of the spherical shell to hold a C-type lamp socket and a C-type lamp bulb in the spherical shell, the top cover having a peripheral wall defining a bottom open chamber, two springy hook plates formed integral with the peripheral wall at two opposite sides and respectively hooked on the periphery of the opening of the spherical shell to secure the top cover to the spherical shell, a plurality of splits cut through the peripheral wall at two opposite lateral sides of each of the springy hook plates, and two springy oblique retaining plates suspended in the bottom open chamber and adapted to hold a C-type lamp socket in the spherical shell.

Abstract: A lamp socket with a water sealing and electric leakage preventing structure, including a channel-like rubber gasket fitted into a top wire groove in a socket body to hold an electric wire and having two slots for the passing of a positive metal contact plate and a negative metal contact plate of the socket body, a rubber cover pad covered on the rubber gasket over the electric wire and compressed against the electric wire and the rubber gasket by a socket cap being fastened to the socket body to seal the periphery of the electric wire and to prevent water from passing to the contact areas between the electric wire and the positive and negative metal contact plates.

Abstract: An electric socket in which the socket body has two outer electric wire supports transversely raised from the two opposite ends of the top wire groove thereof, and an intermediate electric wire support transversely raised from the top wire groove between the positive metal contact plate and the negative metal contact plate, the outer electric wire supports and the intermediate electric wire support having a respective transversely corrugated top edge fitting the transverse cross section of the periphery of the electric wire being mounted in the top wire groove and forced into engagement the periphery of the electric wire to stop rain water from causing an electric short circuit or current leakage.

Abstract: A lamp socket including a rubber top water seal member and a rubber bottom water seal member respectively fastened to two opposite ends of the socket body thereof to stop rain water from passing to the inside of the body, the rubber top water seal member having a bottom mounting groove engaged with the top edge of the socket body, two plug portions fitted into two opposite ends of a transverse wire groove of the socket body to support an electrical wire in the transverse wire groove, and two pairs of wedge blocks forced into close contact with the periphery of the electrical wire at the top by a pressure block of a socket cap, which is fastened to the socket body to hold down the electrical wire, the rubber bottom water seal having an upright annular flange fitted into an annular bottom groove at the bottom end of the socket body, a plurality of upright hooks raised from the upright annular flange and hooked in respective hook hole in the socket body, and an inward annular flap forced into close contact with

Abstract: A lamp socket in which a rubber water sealing cushion is mounted in a top recess at the center of the transversely grooved top wall of the socket body and covered around the electric wire to protect the positive metal contact plate against outside water, a rubber socket is mounted inside the socket body and covered around the positive metal contact plate, having an outward flange which is pressed on the base top of the lamp bulb and circularly covered over the tip contact thereof, and a metal strip transversely suspending on the inside and forced by the tip contact of the lamp bulb into contact with the positive metal contact plate.

Abstract: A safety lamp socket in which the center metal contact plate is fastened to a first through hole on the socket body, having a flanged transverse head at one end fastened to a retaining groove inside the first through hole, a pointed upright tip disposed outside the first through hole for piercing the electric wire to make electrical contact with one conductor thereof, and a springy tail at an opposite end disposed inside the socket body and supported on at least one first inside projecting bearing portion inside the socket body for contact with the tip contact of the lamp bulb.