Noise reduction circuit and mobile terminal
A circuit and noise reduction technology, applied in transducer circuits, electrical components, sensor components, etc., can solve problems affecting call quality, TDD noise, etc.
Active Publication Date: 2021-04-27
SHANGHAI TRANSSION CO LTD
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Problems solved by technology
[0004] The main purpose of the present invention is to propose a noise reduction circuit and a mobile terminal, aiming to solve the problem that when the user talks through the earphone, the RF signal is collected by the microphone output pin MIC, and transmitted to the mobile terminal of the calling party, generating TDD noise. Affect call quality
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[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.
[0027] It should be noted that if there are directional indications (such as up, down, left, right, front, back...) in the embodiment of the present invention, the directional indications are only used to explain how to move in a certain posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.
[0028] In addition, if there are descriptions involving "first", "second" an...
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The invention discloses a noise reduction circuit and a mobile terminal. The noise reduction circuit includes an earphone socket, an FM signal demodulation circuit and a high-pass filter circuit. The earphone socket includes an earphone jack, a grounding pin arranged in the earphone jack, and a microphone output pin. , the ground pin is connected to the first end of the high-pass filter circuit, and the second end of the high-pass filter circuit is connected to the input end of the FM signal demodulation circuit; when the ground pin is inserted into the earphone male, the antenna signal is received through the earphone male and passed through The filter circuit filters out the low-frequency signal in the antenna signal and outputs it; the FM signal demodulation circuit detects the received antenna signal to obtain the FM signal and RF envelope signal; the high-pass filter circuit filters out the FM signal demodulation circuit to ground pin the RF envelope signal. The invention solves the problem that when the user talks through the earphone, the RF signal is collected by the microphone output pin MIC, and transmitted to the mobile terminal of the talking party, thereby generating TDD noise and affecting the talking quality.
Description
technical field [0001] The invention relates to the technical field of electronic circuits, in particular to a noise reduction circuit and a mobile terminal. Background technique [0002] At present, mobile phones generally have the function of specifically receiving FM broadcast signals, and generally use a shared earphone cable as an FM antenna. [0003] The headphone cable can not only collect FM signals, but also collect RF signals. Due to the specific nonlinear devices inside the FM chip, when the FM signal is detected, the RF signal envelope will also be detected, and the detected RF envelope signal at 217Hz is It will become noise and feed back to the MIC end of the earphone. When using the earphone to talk, the receiver of the other party will hear obvious TDD noise, which will affect the quality of the call. Contents of the invention [0004] The main purpose of the present invention is to propose a noise reduction circuit and a mobile terminal, aiming to solve t...
Claims
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IPC IPC(8): H04R3/00
CPCH04R3/00H04R2410/05
Inventor 朱勇
Owner SHANGHAI TRANSSION CO LTD