Abstract

A circuit for a front-end tunable filter of a communication and broadcast receiver and a tuning method thereof are described herein. In one aspect, the circuit of the tunable filter may be independent of the signal reception link of the receiver. The pre-filter (104) includes a variable capacitance (146) which is adjusted by a tuning signal (160). A negative resistance element (144) and the pre-filter (104) may form an oscillator. The negative resistance element (144) is controlled by an amplitude control signal (162) outputted from an oscillation amplitude control circuit (142). The oscillation amplitude control circuit (142) stabilizes the amplitude of a radio frequency signal (130) in a preset range. An oscillation frequency control circuit (140) stabilizes the frequency of the signal (130) in a preset frequency range by a tuning signal (160). The tuning is completed until both of the amplitude and the frequency of the oscillation signal meet the preset ranges.

IPC Classes  ?

• H04B 1/10 - Means associated with receiver for limiting or suppressing noise or interference
• H04B 1/16 - Circuits
• H03H 7/01 - Frequency selective two-port networks
• H04B 1/18 - Input circuits, e.g. for coupling to an antenna or a transmission line

Abstract

A processing chip for a digital microphone and related input circuit and a digital microphone are described herein. In one aspect, the input circuit for a processing chip of a digital microphone includes: a PMOS transistor, a resistor, a current source, and a low-pass filter. The described processing chip possesses high anti high-frequency interference capabilities and the described input circuit possesses high high-frequency power supply rejection ratio.

IPC Classes  ?

• H04R 3/00 - Circuits for transducers
• H04R 19/04 - Microphones
• H04R 3/06 - Circuits for transducers for correcting frequency response of electrostatic transducers

Abstract

A device for obtaining a RCC signal and related methods are described herein improves the reliability of the RCC signal reception and demodulation. In one aspect, a device configured to obtain a RCC signal includes: a receiving circuit to receive an analog AM RCC signal and to process said analog AM RCC signal to generate a digital AM RCC signal; and a demodulation circuit in connection with said receiving circuit, to demodulate said digital AM RCC signal to generate the RCC signal. In another aspect, a method for obtaining a RCC signal includes: processing a received analog AM RCC signal to generate a digital AM RCC signal; and demodulating said digital AM RCC signal to generate said RCC signal. Since the digital processing method is more reliable than the analog processing method, the reliability of RCC signal reception and demodulation are improved.

IPC Classes  ?

• H03D 1/24 - Homodyne or synchrodyne circuits for demodulation of signals wherein one sideband or the carrier has been wholly or partially suppressed
• G04R 20/10 - Tuning or receiving; Circuits therefor

Abstract

A power supply device, a processing chip for a digital microphone and related digital microphone are described herein. In one aspect, a power supply device includes: at least two cascaded low-dropout linear regulators. In another aspect, a processing chip for digital microphone includes a processing module and a power supply module, wherein the power supply modules includes at least two cascaded low dropout linear regulators. In another aspect, a digital microphone includes a microphone and a processing chip, wherein the processing chip includes a processing module and a power supply module, wherein the power module includes at least two cascaded low-dropout linear regulators. Embodiments described herein provide a power supply device with higher PSRR.

IPC Classes  ?

• G05F 1/40 - Regulating voltage or current wherein the variable is actually regulated by the final control device is ac using discharge tubes or semiconductor devices as final control devices
• H04R 1/04 - Structural association of microphone with electric circuitry therefor