This design uses Common-Emitter Amplifier (Class A) with 2N3904 Bipolar Junction Transistor.
Use “Voltage Divider Biasing” to reduce the effects of varying β (= ic / ib) (by holding the Base voltage constant)
Base Voltage (Vb) = Vcc * [R2 / (R1 + R2)]
Use Coupling Capacitors to separate the AC signals from the DC biasing voltage (which only pass AC signals and block any DC component).
Use Bypass Capacitor to maintain the Q-point stability.
To determine the value of each component, first set Q-point close to the center position of the load line. (RL is the resistance of the speaker.)
CPCI_E標準規范 CompactPCI? Express SpecificationThe documents in this section may be useful for reference when reading the specification. The revision listed for each document is the latest revision at the time this specification was published. Newer revisions of these documents may exist, so refer to the newest revision. Many of these documents are referenced throughout this specification. Refer to the newest revision of the document unless a specific revision is referenced. ? PCI Express Base Specification 3.0. PCI Special Interest Group (PCI-SIG). ? PCI Express Card Electromechanical (CEM) Specification 3.0. PCI Special Interest Group (PCI-SIG). ? PCI Express to PCI/PCI-X Bridge Specification, Rev. 1.0. PCI Special Interest Group (PCI-SIG). ? PCI Express Jitter White Paper. PCI Special Interest Group (PCI-SIG). ? PCIe Rj Dj BER White Paper. PCI Special Interest Group (PCI-SIG). ? PHY Electrical Test Specification for PCI Express Architecture. PCI Special Interest Group (PCI SIG). ? System Management Bus (SMBus) Specification, Version 2.0. Smart Battery System Implementer’
本設計介紹了一種基于STM32單片機控制的智能水杯,可利用插口式電源或無線充電底座為加熱器提供能量,并在達到某種飲品所需溫度時進行保溫。水杯內置充電電池,可選用USB接口或無線充電。在水杯內部設置無線模塊,用戶利用手機App與水杯進行匹配進行加熱操作,加熱完后水杯會通過手機App和液晶顯示屏實時反饋液體溫度,通過指示燈顯示電量情況等,給用戶進行提醒。該智能水杯設計創新,實用價值較高。This paper introduces an intelligent water cup based by STM32 microcontroller,it can provide energy for the heater by socket type power supply or wireless charging base,and hold temperature needed for some kind of drink.Builtedin rechargeable battery,water cup can use USB or wireless charging.The wireless module is set up inside it,and customers can use mobile App to match and heat.After heating,water cup feeds back liquid temperature through the mobile App,and then displays on LCD,reminds users through the indicator light.The intelligent water cup is designed innovatively and has high practical value.
數字頻率計是電工電子中常用的測量儀器,數字頻率計通過用輸入待測信號對一特定長度的信號進行計數,從而得出頻率并通過數碼管直觀的顯示出來。本文提出了一種與輸入同步的數字頻率計的設計,提高了頻率計的精度,設計采用Multisim軟件進行設計和仿真的過程,介紹了其工作原理,硬件電路設計和仿真的過程。設計采用了Multisim軟件進行設計和仿真,設計結果得到的驗證。Digital frequency counter is used to measure the frequency of a signal.It is common to use a multivibrator to generate a standard 1 second time base signal and count input signal gated by this signal.However,the asynchronous of this time base signal with input signal will bring errors.In this paper,a high precision frequency counter which use synchronized time base signal generator is proposed.This frequency counter is designed and simulated by Multisim tools and result is verified.
le flows through MOS channel while Ih flows across PNP transistor Ih= a/(1-a) le, IE-le+lh=1/(1-a)' le Since IGBT has a long base PNP, a is mainly determined by ar si0 2ar= 1/cosh(1/La), La: ambipolar diff length a-0.5 (typical value)p MOSFET channel current (saturation), le=U"Cox"W(2"Lch)"(Vc-Vth)le Thus, saturated collector current Ic, sat=1/(1-a)"le=-1/(1-a)"UCox"W/(2Lch)"(Vo-Vth)2Also, transconductance gm, gm= 1/(1-a)"u' Cox W/Lch*(Vo-Vth)Turn-On1. Inversion layer is formed when Vge>Vth2. Apply positive collector bias, +Vce3. Electrons flow from N+ emitter to N-drift layer providing the base current for the PNP transistor4. Since J1 is forward blased, hole carriers are injected from the collector (acts as an emitter).5. Injected hole carriers exceed the doping level of N-drift region (conductivity modulation). Turn-Off1. Remove gate bias (discharge gate)2. Cut off electron current (base current, le, of pnp transistor)
隨著新研發單板上高速Serdes信號的增多，信號完整性測試顯的越來越重要，本文檔圍繞Serdes信號的眼圖抖動測試總結一些測試注意事項。新研發單板上高速Serdes信號速率高達2.45G，一些時鐘信號上升/下降沿達到400ps左右，必然需要測量Serdes信號的眼圖、抖動，在這里總結一些測試經驗和注意事項。UBPG1單板上有如下幾種高速數據SERDES信號：1. GE SERDES接口(SGMII接口標準)2. AIF SERDES接口(CPRI接口標準)3. IQ SERDES接口(類CPRI接口標準，自定義幀格式)4. 光口 SERDES接口(CPRI接口標準)對于SERDES信號，其信號電氣特性由IEEE協議規定，在協議中會給出相應的眼圖測試模板及抖動指標，部分芯片廠家會在DATASHEET中給出單獨的眼圖測試模板及抖動指標（一般會比協議要求的更寬松）。UBPG1單板上的SERDES接口按電氣特性分有兩種，一種是SGMII接口（用1000-BASE-CX模板，IEEE協議39節）；一種是CPRI接口（用XAUI模板，IEEE協議49節）。
