CN2816894Y

CN2816894Y - Audio frequency circuit of inhibiting noise interference

Info

Publication number: CN2816894Y
Application number: CN 200520043862
Authority: CN
Inventors: 刘昌信
Original assignee: Shanghai Huanda Computer Technology Co Ltd; Mitac International Corp
Current assignee: Shanghai Huanda Computer Technology Co Ltd; Mitac International Corp
Priority date: 2005-07-28
Filing date: 2005-07-28
Publication date: 2006-09-13
Anticipated expiration: 2015-07-28

Abstract

The utility model relates to an audio frequency circuit for suppressing noise interference, which comprises a base board, a signal handler, at least one audio frequency socket, at least one filtering assembly and at least one inductance assembly, wherein the signal handler is arranged in an analogue grounding area of the base board, the audio frequency socket is arranged in a casing grounding area of the base board, and the inductance assembly is connected between the analogue grounding area and the casing grounding area of the base board, which can avoid bringing the noise of the analogue grounding area to the audio frequency socket; in addition, the filtering assembly can filter the noise of audio signals so as to suppress the interference of electromagnetic waves.

Description

The voicefrequency circuit that suppresses noise

Technical field

The utility model relates to a kind of voicefrequency circuit, and particularly relevant for a kind of voicefrequency circuit that suppresses noise.

Background technology

Early stage ISA sound card has scattered a large amount of assemblies because integrated level is not high on the sound card, afterwards along with the development of technology and technology level, the sound card of single-chip occurred, only just can finish all functions of sound card with chip piece.But, make that the signal to noise ratio (S/N ratio) of ISA sound card is unsatisfactory because the numerical portion of sound card and partly integrated being in the same place of simulation are difficult to reduce the influence of Electromagnetic Interference (EMI) to the simulation part.

AC ' 97 standards then propose " twin-core sheet " structure, and the digital circuit that is about to Audio Processing is separated with mimic channel two parts, and each part is used chip piece separately.The circuit of simulation part is to be handled by the small chip of " Audio Codec " (audio-frequency signal coding/code translator), and the circuit of numerical portion is then handled by the chip of " DigitalControl " (digitial controller).AC ' 97 standards combine the advantage of digital processing and simulation process two aspects, have reduced on the one hand the noise (noise) that may occur when being converted to digital circuit by analog line, have built purer tonequality; On the other hand, with audio handle be integrated into chipset after, can further reduce cost.

Yet, in the wiring of voicefrequency circuit, for fear of simulating signal and digital signal mutual interference mutually, can independently cut out on the substrate analogue ground district (AGND) allow sound signal cabling usefulness, and do with digital grounding district (DGND) and to separate.But because analogue ground district (AGND) is usually less than digital grounding district (DGND), and noise is more, thus when going up transmission, analogue ground district (AGND) easily grass is come out when sound signal, and can't effectively suppress Electromagnetic Interference.

Summary of the invention

The purpose of this utility model is exactly that a kind of voicefrequency circuit that suppresses noise is being provided, and in the time of avoiding sound signal to transmit in the analogue ground district grass is come out, to reach the inhibition anti noise.The utility model proposes a kind of voicefrequency circuit of inhibition noise, comprise a substrate, have a digital grounding district, an analogue ground district and a chassics earth district; One signal processor is disposed in this analogue ground district of this substrate; At least one audio socket is disposed in this chassics earth district of this substrate, and is connected to this signal processor by a signals layer of this substrate; At least one filtering unit, an end of this filtering unit are connected between this analogue ground district and this chassics earth district of this substrate, and the other end of this filtering unit is connected in this signals layer of this substrate; And at least one Inductive component, be connected between this analogue ground district and this chassics earth district of this substrate.

Described according to preferred embodiment of the present utility model, above-mentioned signal processor for example is audio-frequency signal coding/code translator (Audio Codec).In addition, audio socket for example comprises microphone jack, loudspeaker socket, earphone socket and recording socket.

Described according to preferred embodiment of the present utility model, the area of said machine casing access area is for example smaller or equal to the analogue ground district.

Described according to preferred embodiment of the present utility model, above-mentioned filtering unit for example is choke-condenser filter (LC filter).

The utility model is because of cutting the part area of original analogue ground district on audio socket, forming an independently chassics earth district, and disposes a plurality of filtering units and at least one Inductive component between analogue ground district and chassics earth district.Therefore, can avoid the noise in the analogue ground district to be brought on the audio socket, and the noise on the sound signal can be filtered, to reach the effect that EMI suppresses.

The utility model is above-mentioned to be become apparent with other purpose, feature and advantage in order to allow, and preferred embodiment cited below particularly, and conjunction with figs. are described in detail below.

Description of drawings

Fig. 1 illustrates a kind of synoptic diagram that suppresses the voicefrequency circuit of noise of the utility model one preferred embodiment.

Embodiment

Please refer to Fig. 1, it illustrates a kind of synoptic diagram that suppresses the voicefrequency circuit of noise of the utility model one preferred embodiment, has in being applicable on the motherboard of control chip.This voicefrequency circuit 100 that suppresses noise mainly comprises a substrate 110, a signal processor 120, an audio socket 130, most individual filtering unit 140～142 and at least one Inductive component 150.In the present embodiment, do not share same ground plane for making digital signal and simulating signal on the substrate 110, substrate 110 is divided into three zones with its ground area, comprises a digital grounding district 112, an analogue ground district 114 and a chassics earth district 116.Therefore, digital signal on the substrate 110 can 112 places, digital grounding district signals layer on transmit, and the simulating signal on the substrate 110 can be transmitted on the signals layer at analogue ground district 114 and 116 places, chassics earth district, can avoid the interference between signal between the two and produces noise.

In addition, signal processor 120 for example is audio-frequency signal coding/code translator, it is disposed at the surface of 114 regions, analogue ground district of substrate 110, and the signals layer of crossing substrate 110 is connected to the audio socket 130 that is positioned in the chassics earth district 116, and audio socket 130 for example comprises microphone jack, loudspeaker socket, earphone socket and recording socket etc., spreads out of by loudspeaker or earphone in order to connect by sound signal that microphone received or with sound signal.

It should be noted that, because signal processor 120 is in different analogue ground planes respectively with audio socket 130, be that chassics earth district 116 is by a formed analogue ground plane independently, the ground area of cutting substrate 110 on audio socket 130, itself and contiguous analogue ground district 114 spacing of being separated by, and Inductive component 150 cross-over connections are in the analogue ground district 114 and chassics earth district 116 of spacing both sides, in order to avoid the noise in the analogue ground district 114 to be brought on the audio jack 130 in chassics earth district 116, to improve the quality of signal transmission.In the present embodiment, the area in chassics earth district 116 is smaller or equal to the area in analogue ground district 114.

In addition, filtering unit for example is the wave filter of choke-condenser filter (LC filter) or other anti-electromagnetic interference (EMI).One end of filtering unit 140～142 is coupled between analogue ground district 114 and the chassics earth district 116, and the other end of filtering unit 140～142 for example is coupled to the signal wire (not illustrating) in order to signal contact between transmission of audio socket 130 and the signal processor 120.The utility model can filter the high frequency noise on the sound signal by filtering unit 140～142, to reach the effect that EMI suppresses.

In sum, the utility model is because of cutting the part area of original analogue ground plane on audio socket, to form an independently chassics earth district, the analogue ground at itself and signal processor place distinguishes, and disposes a plurality of filtering units and at least one Inductive component between analogue ground district and chassics earth district.Therefore, can avoid the noise in the analogue ground district to be brought on the audio socket, and the noise on the sound signal can be filtered.Based on above-mentioned, on the effect that suppresses Electromagnetic Interference, the noise on the sound signal can reduce effectively, and tonequality is more clear, and then improves the quality of signal transmission.

Though the utility model discloses as above with preferred embodiment; right its is not in order to limit the utility model; anyly have the knack of this operator; in the spirit and scope that do not break away from the utility model; when doing a little change and retouching, therefore protection domain of the present utility model is as the criterion when looking the accompanying Claim book person of defining.

Claims

1. voicefrequency circuit that suppresses noise is characterized in that comprising:

One substrate has a digital grounding district, an analogue ground district and a chassics earth district;

One signal processor is disposed in this analogue ground district of this substrate;

At least one audio socket is disposed in this chassics earth district of this substrate, and is connected to this signal processor by a signals layer of this substrate;

At least one filtering unit, an end of this filtering unit are connected between this analogue ground district and this chassics earth district of this substrate, and the other end of this filtering unit is connected in this signals layer of this substrate; And

At least one Inductive component is connected between this analogue ground district and this chassics earth district of this substrate.

2. suppress the voicefrequency circuit of noise according to claim 1, it is characterized in that: this signal processor is audio-frequency signal coding/code translator.

3. suppress the voicefrequency circuit of noise according to claim 1, it is characterized in that: this audio socket comprise microphone jack, loudspeaker socket, earphone socket and recording socket one of them.

4. suppress the voicefrequency circuit of noise according to claim 1, it is characterized in that: the area in this chassics earth district is smaller or equal to this analogue ground district.

5. suppress the voicefrequency circuit of noise according to claim 1, it is characterized in that: this filtering unit is a choke-condenser filter.