MPL-B960B-SJ72AA

電磁兼容性（EMC）”主要分為兩種，一種是設(shè)備本身的電磁噪聲對(duì)其他設(shè)備或人體帶來(lái)的影響（電磁干擾，EMI：Electromagnetic Interference， Emission），另一種是設(shè)備是否會(huì)因來(lái)自外部的電磁干擾而發(fā)生誤動(dòng)作（電磁敏感性EMS：Electromagnetic Susceptibility， Immunity），之所稱(chēng)為“電磁兼容性”，是由于為了避免發(fā)生故障，這兩方面都要兼顧。

以文字的形式寫(xiě)成“定義”是這樣的，理解起來(lái)有點(diǎn)難是吧。下面我將淺顯易懂地、直觀(guān)地解釋一下。我將以大家熟悉的半導(dǎo)體集成電路（LSI、IC）為主角進(jìn)行解說(shuō)。

首先是電磁干擾（EMI或電磁發(fā)射）。如今，已經(jīng)開(kāi)發(fā)出并且在售的LSI和IC種類(lèi)繁多。為了便于說(shuō)明，大致分類(lèi)如下：

①老式三端電源（7805和7905等）和低飽和電源（LDO）等直流電源相關(guān)產(chǎn)品。這些產(chǎn)品要處理的信號(hào)是直流（DC）的。

②差分運(yùn)算放大器（運(yùn)算放大器）、電壓比較器（比較器）、語(yǔ)音信號(hào)處理等相關(guān)的產(chǎn)品。要處理的信號(hào)是基于正弦波的模擬信號(hào)和線(xiàn)性信號(hào)。

③微控制器、存儲(chǔ)器、邏輯等相關(guān)的產(chǎn)品。要處理的信號(hào)是數(shù)字信號(hào)。

④近常用的開(kāi)關(guān)電源和電荷泵電源等電源相關(guān)的產(chǎn)品；LED驅(qū)動(dòng)器、LCD驅(qū)動(dòng)器等顯示相關(guān)的產(chǎn)品；PWM電機(jī)驅(qū)動(dòng)器等驅(qū)動(dòng)相關(guān)的產(chǎn)品。這些LSI和IC是涉及到開(kāi)關(guān)技術(shù)的產(chǎn)品。

其中①和②不產(chǎn)生電磁干擾（EMI），③和④產(chǎn)生電磁干擾（EMI）?？梢院?jiǎn)單的理解為模擬LSI和線(xiàn)性L(fǎng)SI不會(huì)產(chǎn)生電磁噪聲，而數(shù)字LSI和開(kāi)關(guān)LSI會(huì)產(chǎn)生電磁噪聲，這樣說(shuō)可能更直觀(guān)更易懂。

Nortel BCM BRI-4 S/T - 4 Port BRI Module (NT7B76AAAH)

Nortel-Norstar MICS NT8B75AE - A0399899 - 84100-2 Star 

Used Business Digital Office Telephone System by Nortel

Nortel MICS Startalk Flash Voice Mail Telephone System

Nortel NT0H02AB Optera Metro 5x00

One-day shipping available

 Surplus Nortel 8608GTE DS1404044 8Port 1000Base-TE

90 Day Hardware Warranty - Free Shipping!

Nortel Passport 15000 DS3cAAL NTFN91AB

AVAYA NORTEL 8005AC POWER SUPPLY 100-240V DS1405012-E5

Expedited shipping available

NORTEL 2 PORT Secure Router SR1002 T1 SR2101007E5

NORTEL SL-1 QCA74 QRF8 RECTIFIER 48vdc 50A POWER MODULE

Nortel, NT5B42AAAGE5 COMBINATION GATM8 & DSM16 MEDIA ..

1  Nortel BCM50 r3 4x8x8x2x2 BCM 50 3.0 r3.0 bundle

with updated patches loaded

NORTEL NETWORK ADAPTER EXPANSION SLOT ISDN AF2104010

Nortel BCM450 IP Telephony - 16 Seat Code NTC01070KC

Nortel BCM 450 IP Telephony Client - 16 Seat NTC01070KC

Nortel Optera NT0H30KA , WMADF3DDAA , OMX 4-CH BAND-6

Nortel BCM50e Main Unit with Ethernet Router

Com Dev Nortel NTQA51DA Wireless RF Module 2G 1900

One-day shipping available

NORTEL CALL PILOT CP100 RLS3 (10MBX) ENGLISH/FRENCH

Nortel Office Business Telephone System Hosted IP VOIP?

Nortel BCM 50 Base System With Ethernet Router

Nortel Norstar CICS Rls 4.1 with CID Phones and V/Mail

Complete with (4) Phones Voicemail Telephone System

Nortel compact ics Office Phone System w/(4) T7316E VM

Nortel Passport 8003 Switch 8632TXE 8616SXE 8691DF

★★★ Price inc VAT - Good conditon ★★★

Nortel Norstar CallPilot Call Pilot 150 Voicemail

One-day shipping available

Nortel BCM Expansion Cabinet With Redundant Power Suppl

JDSU Nortel DBR SG-DBR Tunable Laser Module, C-Band

Nortel Business Phone System Package #1 w/ 1yr Warranty

1 Nortel BCM200 3.7 8x16 4vm 10 M7310 replace CICS 8X16

NORTEL AS3104004 20-PORT 10/100 CENTILLION SWITCH

Nortel 824KSU with Flash Voicemail and (11) Phones

CallPilot 150 CP150 64-MB Call Pilot Voicemail Nortel

Power supply and mounting bracket included

Nortel Core/ Net Module

Nortel, NTC04010SW BCM450 1.0+5.0/6.0S/W KIT S/W DVD+..

ARIA 130-IP LG NORTEL Digital Key Ph.System.13 H/Sets

Nortel NTCA01QK S-01 , OC-192 WDM TRNSMTTR, SNT4BB1BAA 

[N] Nortel Networks Contivity 4500 Extranet Routing VPN

Nortel NTFW01AB STM-16 LR 1557 Ring tx (FC/PC)

Nortel Networks OC-48 Multiplexer NTN440EA

Nortel NT5C05CF61 200E/48 SWITCH MODE RECTIFIER Refurbi

Nortel Meridian Integrated Conference

Nortel NT5C05CD61 HELIOS RECTIFIER 200/E/48 Refurbished

NORTEL NETWORKS NT8E05BB FDN2400 NET DEMUX HECI SNPQAFE

One-day shipping available

10 Nortel I2004 IP Phone Charcoal Bezel w Poe Adaptor

Nortel BCM400 Business Communications Manager EUC OEM

Nortel DC Rectifier Module

Nortel BCM 4 port ISDN BRI S/T Interface Module 

1 Nortel BCM400 3.7 BCM 400 R3.7 MCDN 8 Voip Gateway

Nortel MFA 150

10  Nortel Norstar T7316E T7316 E Phone NT8B27JAAA

Nortel NTN458RA Breaker Interface Panel 

One-day shipping available

1 Nortel BCM50 r5 4x8x16 BCM 50 5.0 r5.0 4x8 16vm 2ip

with updated patches loaded

Enlarge

Nortel BCM DDIM - Digital Drop & Insert MUX Module

MFG Refurb NIB Nortel NTDW64AA 96

Avaya / Nortel BCM1000e NT7B14AAAF - A0899816 Expansion

1 Nortel BCM50 r5 4x12x16 BCM 50 5.0 r5.0 4x12 16vm 4an

with updated patches loaded

Enlarge

10 Nortel I2004 NTDU82 Icon Keys Charcoal w poe adaptor

10 Nortel I2004 NTDU82 dual port ipphone w/ poe adaptor

1  Nortel BCM50 r5 4x8x8 BCM 50 r5.0 5.0 4x8 8vm

with updated patches loaded

Nortel Meridian Phone System Telephone System VOIP 

Nortel NTLX07AA XA-Core Circuit Pack Refurbished

Nortel Compact ICS Office Phone System w/(4) T7316E VM

Fully Expanded Telephone system with v/mail and phones

Nortel Norstar CICS Telephone system with Voicemail +

Fully Expanded Telephone system with v/mail and phones