在無線通信系統(tǒng)全面進入3G并開始邁向 4G的過程中，使用數(shù)字預(yù)失真技術(shù)（Digital Pre-distortion，以下簡稱DPD）對發(fā)射機的功放進行線性化是一門關(guān)鍵技術(shù)。功率放大器是通信系統(tǒng)中影響系統(tǒng)性能和覆蓋范圍的關(guān)鍵部件，非線性是功放的固有特性。非線性會引起頻譜增長(spectral re-growth)，從而造成鄰道干擾，使帶外雜散達不到協(xié)議標準規(guī)定的要求。非線性也會造成帶內(nèi)失真，帶來系統(tǒng)誤碼率增大的問題。
標簽： DPD 數(shù)字預(yù)失真 算法 驗證方案
上傳時間： 2013-10-19
上傳用戶：yy_cn
首先把功率管的小信號S參數(shù)制成S2P文件,然后將其導(dǎo)入ADS軟件中,在ADS中搭建功率管的輸入輸出端口匹配電路,按照最大增益目標對整個電路進行優(yōu)化,最后完成電路的設(shè)計。
標簽： 小信號 S參數(shù) 功率 放大器設(shè)計
上傳時間： 2013-10-21
上傳用戶：zhangfx728
采用微波仿真軟件AWR對電路結(jié)構(gòu)進行了優(yōu)化和仿真,結(jié)果顯示,在5～12 GHz頻帶內(nèi),復(fù)合晶體管結(jié)構(gòu)的輸出阻抗值更穩(wěn)定,帶寬得到有效擴展,最高增益達到11 dB,帶內(nèi)波動<0.5 dB,在9 GHz工作頻率時,其1 dB壓縮點處的輸出功率為26 dBm。
上傳時間： 2013-11-04
上傳用戶：marten
The LT®6552 is a specialized dual-differencing 75MHzoperational amplifier ideal for rejecting common modenoise as a video line receiver. The input pairs are designedto operate with equal but opposite large-signal differencesand provide exceptional high frequency commonmode rejection (CMRR of 65dB at 10MHz), therebyforming an extremely versatile gain block structure thatminimizes component count in most situations. The dualinput pairs are free to take on independent common modelevels, while the two voltage differentials are summedinternally to form a net input signal.
上傳時間： 2014-12-23
上傳用戶：13691535575
在本課題中，兼顧了效率及線性度，采用自適應(yīng)預(yù)失真前饋復(fù)合線性化系統(tǒng)來改善高功率放大器的線性度。由于加入自適應(yīng)控制模塊，射頻電路不受溫度、時漂、輸入功率等的影響，可始終處于較佳工作狀態(tài)，這使得整個放大系統(tǒng)更為實用，也更具有拓展價值。
上傳時間： 2013-11-21
上傳用戶：xauthu
本文針對傳統(tǒng)儀用放大電路的特點，介紹了一種高共模抑制比儀用放大電路，引入共模負反饋，大大提高了通用儀表放大器的共模抑制能力。
上傳時間： 2013-11-10
上傳用戶：lingfei
交調(diào)失真(IMD)是用于衡量放大器、增益模塊、混頻器和其他射頻元件線性度的一項常用指標。二階和三階交調(diào)截點(IP2和IP3)是這些規(guī)格參數(shù)的品質(zhì)因素，以其為基礎(chǔ)可以計算不同信號幅度下的失真積。雖然射頻工程師們非常熟悉這些規(guī)格參數(shù)，但當(dāng)將其用于ADC時往往會產(chǎn)生一些困惑。本教程首先在ADC的框架下對交調(diào)失真進行定義，然后指出將IP2和IP3的定義應(yīng)用于ADC時必須采取的一些預(yù)防措施。
標簽： ADC 交調(diào)失真
上傳時間： 2014-01-07
上傳用戶：歸海惜雪
Photodiodes can be broken into two categories: largearea photodiodes with their attendant high capacitance(30pF to 3000pF) and smaller area photodiodes withrelatively low capacitance (10pF or less). For optimalsignal-to-noise performance, a transimpedance amplifi erconsisting of an inverting op amp and a feedback resistoris most commonly used to convert the photodiode currentinto voltage. In low noise amplifi er design, large areaphotodiode amplifi ers require more attention to reducingop amp input voltage noise, while small area photodiodeamplifi ers require more attention to reducing op amp inputcurrent noise and parasitic capacitances.
上傳時間： 2013-10-28
上傳用戶：hanbeidang
A fully differential amplifi er is often used to converta single-ended signal to a differential signal, a designwhich requires three signifi cant considerations: theimpedance of the single-ended source must match thesingle-ended impedance of the differential amplifi er,the amplifi er’s inputs must remain within the commonmode voltage limits and the input signal must be levelshifted to a signal that is centered at the desired outputcommon mode voltage.
上傳時間： 2013-11-09
上傳用戶：wweqas
Recent advances in low voltage silicon germaniumand BiCMOS processes have allowed the design andproduction of very high speed amplifi ers. Because theprocesses are low voltage, most of the amplifi er designshave incorporated differential inputs and outputs to regainand maximize total output signal swing. Since many lowvoltageapplications are single-ended, the questions arise,“How can I use a differential I/O amplifi er in a single-endedapplication?” and “What are the implications of suchuse?” This Design Note addresses some of the practicalimplications and demonstrates specifi c single-endedapplications using the 3GHz gain-bandwidth LTC6406differential I/O amplifi er.
標簽： 單端應(yīng)用 差分 放大器
上傳時間： 2013-11-23
上傳用戶：rocketrevenge
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