Abstract: A gain control device comprises a sign bit identification device and a gain determination device. The sign bit identification device is used to receive a data, identify a sign bit, and obtain a position of a time slot corresponding to the sign bit. Also, the data comprises a plurality of bits, wherein the most significant bit of the bits is designed to be a sign bit which is used to represent a positive or negative value of the data. The gain determination device is electrically connected to the sign bit identification device, and the gain determination device is used to determine a gain value for amplifying the data based on the position of the time slot corresponding to the sign bit identified through the sign bit identification device.

Abstract: A gain control device comprises a sign bit identification device and a gain determination device. The sign bit identification device is used to receive a data, identify a sign bit, and obtain a position of a time slot corresponding to the sign bit. Also, the data comprises a plurality of bits, wherein the most significant bit of the bits is designed to be a sign bit which is used to represent a positive or negative value of the data. The gain determination device is electrically connected to the sign bit identification device, and the gain determination device is used to determine a gain value for amplifying the data based on the position of the time slot corresponding to the sign bit identified through the sign bit identification device.

Abstract: An audio multi-standard detection apparatus is provided to pre-record a plurality of audio broadcasting format carrier bands. The detection apparatus includes: a carrier calculation unit and a switch controller. The carrier calculation unit is used for receiving an intermediate frequency signal and calculates the first carrier energy of the intermediate frequency signal in each of the frequency bands. From this first carrier energy, the switch controller determines which frequency bands are existed in the intermediate frequency signal, then analyzes the signal via at least one threshold value to determine the frequency band's primary carrier. The switch controller obtains an effective carrier. Further, the switch controller compares the effective carrier with the pre-recorded carrier bands for selectively outputting the appropriate audio broadcasting format.

Abstract: A test circuit, for checking whether at least one programmable gain amplifier (PGA) operates correctly, includes a signal generator, a gain controller, a test level output circuit, a comparison circuit and an identifying circuit. The signal generator is utilized for outputting a test input signal to a PGA to generate a test output signal. The gain controller is utilized for outputting a gain control signal to the PGA to adjust a gain of the PGA. The test level output circuit is utilized for referring to the test output signal to output a first test level and a second test level. The comparison circuit is utilized for comparing the first and second test levels to generate a result signal. The identifying circuit is utilized for identifying whether the PGA operates correctly according to the result signal.

Abstract: An audio multi-standard detection apparatus is provided to pre-record a plurality of audio broadcasting format carrier bands. The detection apparatus includes: a carrier calculation unit and a switch controller. The carrier calculation unit is used for receiving an intermediate frequency signal and calculates the first carrier energy of the intermediate frequency signal in each of the frequency bands. From this first carrier energy, the switch controller determines which frequency bands are existed in the intermediate frequency signal, then analyzes the signal via at least one threshold value to determine the frequency band's primary carrier. The switch controller obtains an effective carrier. Further, the switch controller compares the effective carrier with the pre-recorded carrier bands for selectively outputting the appropriate audio broadcasting format.

Abstract: A test circuit, for checking whether at least one programmable gain amplifier (PGA) operates correctly, includes a signal generator, a gain controller, a test level output circuit, a comparison circuit and an identifying circuit. The signal generator is utilized for outputting a test input signal to a PGA to generate a test output signal. The gain controller is utilized for outputting a gain control signal to the PGA to adjust a gain of the PGA. The test level output circuit is utilized for referring to the test output signal to output a first test level and a second test level. The comparison circuit is utilized for comparing the first and second test levels to generate a result signal. The identifying circuit is utilized for identifying whether the PGA operates correctly according to the result signal.