射频培训资料

huangdiyua

好东西哦，请顶一下!

【文件名】:06819@52RD_射频培训资料.rar
【格　式】:rar
【大　小】:259K
【简　介】:
【目　录】:

sykwolf

我现在真的很需要资料呀！谢谢！

piao_xue

不值！

peizw

好东西啊！可惜没有那么多的monny!!

water2527

大家都說不值耶
只有你說是好東西
免費ㄅ[em01]

yandavis

呵呵,好东西,通俗易懂

vangreensvan

什么内容锕
应该介绍一下嗄

john019

ELECTRONICS
AND
ELECTROSTATIC DISCHARGES

E.M.C. COUPLINGS

ELECTROMAGNETIC COMPATIBILITY

PRINTED BOARDS

TRANSMISSION MODES AND PATHS


DIFFERENTIAL MODE

                Useful signals transmission







COMMON MODE

                Disturbance signal transmission










CURRENT PATHS













                Low frequency currents                        high frequency currents
                return path                                        return path






POWER SUPPLY AND GROUNDS


COMMON MODE IMPEDANCE

        Ucm :  Icm  Zcm

                Decrease Icm and Zcm in sensitive zones

                Separate noisy (digital) and sensitive (low level analog) circuits (Icm)
                Ground planes without slots  (Zcm)

                For high frequency or fast digital signals a ground plane is necessary because paths
show a higher Z

                No slot in ground plane or supply plane , this would share the plane into two parts
separated by an equivalent impedance














                Between boards , connectors show Z , so Z reduction is acheived by several ground
                pins spread over the whole connector width , this will also decrease the slot length .









LAY OUT AND DECOUPLING

Avoid large distance between PS line and ground line

        PS plane and ground plane is the best solution  noise reduction : 2000 from previous case
        This is mandatory for fast digital circuits and very low level analog .


        Decoupling capacitor provide a close primary supply source for current inrush in ICs.
        These capacitors must be as close as possible to the IC .
        Their connections must be as short as possible SMD are recommended , direct link with planes








        Decoupling capacitors must be also installed on the board edge to decrease the slot at this point
to limit radiation at board edges.


For analog circuits :

        There must not be any variation between the supplies V+ and V-
                Supply path impedance must be reduced (wide and short)
                Lower noisy currents as much as possible in sensitive zones


        Star supply :
                Each circuit has its own supply line
        But :
                The conductor length (Z) is not minimum
                The noisy and sensitive stage supplies
share a common path
There is a large loop surface (supply and signal paths)

Chain supply :
        Short supply links between successive stages ( Z and loop surface)
                The noisy stage is first supplied
                Decoupling at each stage

        This last disposition is prefered for analog
        circuitry , the signal level increasing
progressively along the chain .




For digital circuits :
        There is no signal progression the equipotentiality must be global .
For double sided boards :
the minimum will be a meshed network up to the board edges .


        For multilayer boards :
        A ground plane and a supply plane
        are recommended (no slots)

        Internal planes do not offer
.................[em11]