Abstract: The automatic gain control (AGC) method contains the following steps: producing a feedback signal and transmitting the feedback signal to a signal processing unit to produce a working signal; transmitting the working signal to a first signal control unit to produce a first control voltage; transmitting the first control voltage to a second signal control unit to produce a second control voltage, which is a fixed voltage; and transmitting the second control voltage to an AGC unit where the fixed second control voltage is used as a reference value. As such, when a radio-frequency (RF) input signal varies due to channel loading variation, an RF output signal by the AGC unit can be maintained within a specified dB range.

Abstract: The automatic gain control (AGC) method contains the following steps: producing a feedback signal and transmitting the feedback signal to a signal processing unit to produce a working signal; transmitting the working signal to a first signal control unit to produce a first control voltage; transmitting the first control voltage to a second signal control unit to produce a second control voltage, which is a fixed voltage; and transmitting the second control voltage to an AGC unit where the fixed second control voltage is used as a reference value. As such, when a radio-frequency (RF) input signal varies due to channel loading variation, an RF output signal by the AGC unit can be maintained within a specified dB range.

Abstract: An exhaust muffler device for an internal combustion engine includes an outer housing which defines a sealed chamber and which is connected to opposite inlet and outlet pipes, and an initial expansion subchamber and a pre-outlet subchamber disposed in the sealed chamber. The exhaust gas enters the initial expansion subchamber and mainly flows to a tubular passage in the pre-outlet subchamber to be exhausted through the outlet pipe. Portion of the exhaust gas flows into the sealed chamber and re-enters into a rejoining region of the tubular passage to be entrained in the main stream, thereby attenuating noise of the engine with minimal reduction of engine performance.

Abstract: An exhaust muffler device for an internal combustion engine includes an outer housing which defines a sealed chamber and which is connected to opposite inlet and outlet pipes, and an initial expansion subchamber and a pre-outlet subchamber disposed in the sealed chamber. The exhaust gas enters the initial expansion subchamber and mainly flows to a tubular passage in the pre-outlet subchamber to be exhausted through the outlet pipe. Portion of the exhaust gas flows into the sealed chamber and re-enters into a rejoining region of the tubular passage to be entrained in the main stream, thereby attenuating noise of the engine with minimal reduction of engine performance.

Abstract: A thermal protection circuit includes a driving circuit having a thermal control chip electrically disposed thereon. The driving circuit has a first output terminal for outputting voltage and a second output terminal for outputting thermal control voltage. A compare circuit is electrically connected to the driving circuit. The compare circuit includes a comparator electrically disposed thereon for forming a control voltage thereon. The second output terminal of the thermal control chip is electrically connected to the comparator. The comparator forms a base voltage that is determined on the control voltage and the output voltage. A detection circuit is electrically connected to the compare circuit and includes an input terminal disposed thereon for receiving the control voltage. The detection circuit detects the control voltage for controlling to close/open the thermal protection circuit.

Abstract: A battery charger device is provided with a control switch which connects electrically a rechargeable battery load to a power supply which supplies charging current for charging the battery load. A pulse generator generates a series of pulses that control the control switch to connect and disconnect intermittently the power supply and the battery load. A maximum battery terminal voltage of the battery load is stored in a voltage memory means, and a fractional voltage is derived from the maximum battery terminal voltage. The fractional voltage is compared with a current battery terminal voltage from the battery load. A control signal is generated so as to prevent the control switch from receiving the pulses from the pulse generator, thereby disconnecting the power supply from the battery load so as to terminate charging of the battery load when the current battery terminal voltage is less than the fractional voltage.