【正文】 clipping occurs。s stability can be quantified by a socalled stability factor. There are several different stability factors, such as the Stern stability factor and the Linvil stability factor, which specify a condition that must be met for the absolute stability of an amplifier in terms of its twoport parameters. Electronic amplifiers Main article: Electronic amplifier There are many types of electronic amplifiers, monly used in radio and television transmitters and receivers, highfidelity (hifi) stereo equipment, microputers and other electronic digital equipment, and guitar and other instrument amplifiers. Critical ponents 中北大學(xué) 2021 屆畢業(yè)設(shè)計(jì)說(shuō)明書(shū) 第 5 頁(yè) 共 15 頁(yè) include active devices, such as vacuum tubes or transistors. A brief introduction to the many types of electronic amplifier follows. Power amplifier The term power amplifier is a relative term with respect to the amount of power delivered to the load and/or sourced by the supply circuit. In general a power amplifier is designated as the last amplifier in a transmission chain (the output stage) and is the amplifier stage that typically requires most attention to power efficiency. Efficiency considerations lead to various classes of power amplifier: see power amplifier classes. Vacuum tube (valve) amplifiers Main article: Valve amplifier The glow from four Electro Harmonix KT88 brand power tubes lights up the inside of a Traynor YBA200 guitar amplifier According to Symons, while semiconductor amplifiers have largely displaced valve amplifiers for low power applications, valve amplifiers are much more cost effective in high power applications such as radar, countermeasures equipment, or munications equipment (p. 56). Many microwave amplifiers are specially designed valves, such as the klystron, gyrotron, traveling wave tube, and crossedfield amplifier, and these microwave valves provide much greater singledevice power output at microwave frequencies than solidstate devices (p. 59).[2] Valves/tube amplifiers also have niche uses in other areas, such as in russian military aircraft, for their EMP tolerance niche audio for their sound qualities Transistor amplifiers Main articles: Transistor, Bipolar junction transistor, Audio amplifier, and MOSFET The essential role of this active element is to magnify an input signal to yield a significantly larger output signal. The amount of magnification (the forward gain) is determined by the external circuit design as well as the active device. Many mon active devices in transistor amplifiers are bipolar junction transistors (BJTs) and metal oxide semiconductor fieldeffect transistors (MOSFETs). 中北大學(xué) 2021 屆畢業(yè)設(shè)計(jì)說(shuō)明書(shū) 第 6 頁(yè) 共 15 頁(yè) Applications are numerous, some mon examples are audio amplifiers in a home stereo or PA system, RF high power generation for semiconductor equipment, to RF and Microwave applications such as radio transmitters. Transistorbased amplifier can be realized using various configurations: for example with a bipolar junction transistor we can realize mon base, mon collector or mon emitter amplifier。射頻放大器往往在最大功率增益 所 取，而音頻放大器 的電壓增益和儀表放大器將更加經(jīng)常指定（因?yàn)榉糯笃鞯妮斎胱杩?，往往?huì)比源阻抗較高，負(fù)載阻抗高于放大器的輸出阻抗）。因此，這是也是眾所周知的 3 dB 帶寬。專(zhuān)業(yè)旅游放大器往往輸入和 /或輸出濾波大力限制頻率超過(guò) 20赫茲， 20 赫茲的反應(yīng) 。 A 類(lèi)放大器是非常低效的 1020％之間，與 25的輸出直接耦合％最大效率。 AB 類(lèi)放大器是現(xiàn)代之間通常3555％，其中 ％的理論最大效率。此是，由于生產(chǎn)效率損失按損失的能源產(chǎn)品的過(guò)程中能量轉(zhuǎn)換熱能的原因。信封跟蹤設(shè)計(jì)能夠?qū)崿F(xiàn)高達(dá) 60％的效率，通過(guò)調(diào)節(jié)與信號(hào)的包絡(luò)的電源電壓在線路放大器。對(duì)于這些放大器， 1 分貝壓縮點(diǎn)的定義是：輸入功率（或輸出功率）當(dāng)增益為 1分貝的小信號(hào)增益比少。 噪音 這是一個(gè)多大的噪音是在放大過(guò)程中引入的措施。 輸出動(dòng)態(tài)范圍 輸出動(dòng)態(tài)范圍的范圍，通常以 dB 給出了最小和最大之間的有用的輸出水平。 壓擺率 壓擺率是最高的輸出變化率，通常在每秒（或微秒伏特引用）。 建立時(shí)間和振鈴 為輸出解決在最終價(jià)值的一定百分比，例如 ％（所需的時(shí)間）被稱(chēng)為沉淀時(shí)間，通常是示波器垂直放大器和高精度測(cè)量系統(tǒng)中指定。 穩(wěn)定性 穩(wěn)定是符合所有反饋放大器的問(wèn)題，無(wú)論是反饋結(jié)果無(wú)意或有意添加。有幾種不同的穩(wěn)定因素，如斯特恩穩(wěn)定的因素和 Linvil 穩(wěn)定因素，其中一個(gè)必須指定為放大器的絕對(duì)穩(wěn)定性會(huì)見(jiàn)了它的兩個(gè)端口參數(shù)方面的條件。 功率放大器 中北大學(xué) 2021 屆畢業(yè)設(shè)計(jì)說(shuō)明書(shū) 第 13 頁(yè) 共 15 頁(yè) 術(shù)語(yǔ) “ 功率放大器 ” 是一個(gè)關(guān)于交付給負(fù)載和發(fā)電量的相對(duì)長(zhǎng)期 /或由電源電路來(lái)源。許多微波放大器是專(zhuān)門(mén)設(shè)計(jì)的閥門(mén)，如速調(diào)管，回旋管，行波管，交叉場(chǎng)放大器，這些微波閥門(mén)提供更大的單器件在比固態(tài)裝置（第 59頁(yè)的輸出功率微波頻率） [2]。 應(yīng)用多不勝數(shù)，一些常見(jiàn)的例子是音頻放大器在家庭立體聲或擴(kuò)音系統(tǒng)，射頻半導(dǎo)體設(shè)備的高發(fā)電，射頻和微波無(wú)線電發(fā)射器等應(yīng)用程序。 全差分放大器（ FDA）的 主要文章：全差分放大器 全差分放大器是一種固態(tài)集成電路放大器，采用了與它的傳遞函數(shù)或增益控制的外部反饋。步反應(yīng)和過(guò)沖的某些要求是必要的，以便接受電視圖像顯示方式。 分布式放大器 主要文章：分布式放大器 這些使用的傳輸線路，暫時(shí)分裂的信號(hào)和健全各部分分離出來(lái)，以實(shí)現(xiàn)更高的帶寬比可以從一個(gè)單一的擴(kuò)音設(shè)備獲得 的。 開(kāi)關(guān)模式放大器 這些非線性放大器比線性放大器的效率要高得多，其中，用于節(jié)能證明額外的復(fù)雜性。 速調(diào)管 主條目：速調(diào)管 行波管放大器很相似，但功能更強(qiáng)大，用特定頻率的 “ 甜蜜點(diǎn) ” 。因此，一個(gè)高帶寬放大器需要高英尺（至少 310 倍的放大器帶寬）晶體管，以實(shí)現(xiàn)高帶寬。 晶體管的操作，高電流密度高的 fT 為了實(shí)現(xiàn)高帶寬的擴(kuò)增。技術(shù)：大學(xué)的研究人員已經(jīng)開(kāi)發(fā)相結(jié)合三個(gè)階段的放大器的設(shè)計(jì)與實(shí)現(xiàn)理想的增益，大帶寬，低功耗，低輸入 /輸出反射系數(shù)，低損耗寬帶放大器的設(shè)計(jì)方法，可靠性好。 隨著寬帶放大器的發(fā)明，晶體管的典型操作電流密度，但高放大器的帶寬仍然可以實(shí)現(xiàn)。這種優(yōu)勢(shì)是非常 有用的寬帶放大器，它們可以很容易地級(jí)聯(lián)以及