【正文】 這個(gè)優(yōu)點(diǎn)允許所有類(lèi)型的電視接收器在 屏幕顯示 菜單系統(tǒng)上進(jìn)行視頻操作 。 這對(duì)于使用單一的地面線(xiàn)是方便的；然而，電流通過(guò)地面導(dǎo)線(xiàn)和運(yùn)行在電路卡的個(gè)人計(jì)算機(jī)能引起數(shù)百次錯(cuò)誤 。 內(nèi)在的增益電阻， R1 和 R2,被整理到 k?的一個(gè)絕對(duì)值 大小， 允許增益 用 單一外部電阻 精確可編程 。 通過(guò) Q1A1 R1 環(huán) 和 Q2A2 R2 環(huán) 的反饋 維持 持續(xù)的 輸入裝置 Q1 和 Q2 的 整流第 19 頁(yè) 共 20 頁(yè) 器 電流 ,因 此外部增益設(shè)定電阻 RG的輸入電壓 留 有印象。 對(duì)于輸入偏移電流的地面反饋 輸入偏移電流是使這種單片機(jī)的輸入電晶體偏移的必需的那些電流 。 60 mA 數(shù)個(gè) 小 時(shí)。 無(wú)紙化調(diào)試能夠由這種功能來(lái)完成 。 6. 軟件支持系統(tǒng) 1993年 7月 1日 是所有的電視制造業(yè)者 實(shí)施 關(guān)閉型工作臺(tái)系統(tǒng) 的 截止期限。 4． 單一端口隨機(jī)存取儲(chǔ)存器實(shí)現(xiàn) 單一端口顯示隨機(jī)存取儲(chǔ)存器 的時(shí)間分配 顯示隨機(jī)存取儲(chǔ)存器通過(guò)同步到中央處理器的時(shí)鐘的行地址和列地址來(lái)訪(fǎng)問(wèn) 。 這需要程序的顯示控制路徑非?？斓剡\(yùn)行 。 特 性產(chǎn)生只讀存儲(chǔ)器 具有 關(guān)閉型工作臺(tái)格式 112個(gè)前 置 組合特性字型 和 6個(gè)特性字型的能力。 控制區(qū)段由模式和時(shí)間安排控制電路 , 垂直的位置控制電路 , 和水平的位置控制電路 所組成 。 除此之外，這種 大規(guī)模集成 區(qū)別在奇數(shù) 和偶數(shù)區(qū) 間 ， 而且轉(zhuǎn)移信號(hào) (O/E)。 通過(guò)自身產(chǎn)生水平同步信號(hào)和垂直同步信號(hào)，這個(gè)裝置從 21線(xiàn)提取工作臺(tái)信號(hào) 。 因 為前端 大規(guī)模集成 是用雙極性 技術(shù)設(shè)計(jì) 的 ，它在弱 信號(hào) 或 非正常 信號(hào)條件 下甚至能 提供非常穩(wěn)定的操作。 這種新型單片機(jī)由于它的 40ppm最大非線(xiàn)性的高 精確度 ， 50μV 最大值的 低 偏移電壓和 181。 在 1991年 4月 12號(hào)確定的規(guī)則中 , 規(guī)定 可選擇 的 本文模式 的 FCC, 因此 反映廉價(jià)的系統(tǒng)上的那個(gè)委員會(huì)。 for best CMR over frequency, the shield should be properly driven. Ground returns for input bias currents Input bias currents are those currents necessary to bias the input transistors of these microcontrollers. There must be a direct return path for these currents. Therefore, when amplifying input sources, such as transformers or accoupled sources, there must be a dc path from each input to ground. Refer to A Designer’s Guide to these microcontrollers for more information regarding applications. Simplified Schematic of this microcontroller This new microcontroller is a new microcontroller based on a modification of the classic approach. Absolute value trimming allows the user to program gain accurately (to % at G = 100) with only one resistor. Monolithic construction and laser wafer trimming allow the tight matching and tracking of circuit ponents, thus ensuring the high level of performance inherent in this circuit. The input transistors Q1 and Q2 provide a single differentialpair bipolar input for high precision, yet offer 10第 10 頁(yè) 共 20 頁(yè) lower input bias current thanks to processing. Feedback through the Q1A1R1 loop and the Q2A2R2 loop maintains constant collector current of the input devices Q1 and Q2, thereby impressing the input voltage across the external gain setting resistor RG. This creates a differential gain from the inputs to the A1/A2 outputs given by G = (R1 + R2)/RG + 1. The unitygain subtractor, A3, removes any monmode signal, yielding a singleended output referred to the REF pin potential. The value of RG also determines the transconductance of the preamp stage. As RG is reduced for larger gains, the transconductance increases asymptotically to that of the input transistors. This has three important advantages: (a) Openloop gain is boosted for increasing programmed gain, thus reducing gain related errors. (b) The gainbandwidth product (determined by C1 and C2 and the preamp transconductance) increases with programmed gain, thus optimizing frequency response. (c) The input voltage noise is reduced to a value of 9 nV/Hz, determined mainly by the collector current and base resistance of the input devices. The internal gain resistors, R1 and R2, are trimmed to an absolute value of k?, allowing the gain to be programmed accurately with a single external resistor. Other fields Instrumentation amplifiers like This new microcontroller offer high CMR, which is a measure of the change in output voltage when both， inputs are changed by equal amounts. These specifications are usually given for a fullrange input voltage change and a specified, source imbalance. For optimal CMR ,the 第 11 頁(yè) 共 20 頁(yè) reference terminal should be tied to a low， impedance point, and differences in capacitance and resistance， should be kept to a minimum between the two inputs. In many applications shielded cables are used to minimize noise, and for best CMR over frequency the shield should be properly driven. The capacitances of input cable shields, thus minimizing the capacitance mismatch between the inputs. Since This new microcontroller output voltage is developed with respect to the potential on the reference terminal, it can solve many grounding problems by simply tying the REF pin . To isolate low level analog signals from a noisy digital environment, many dataacquisition ponents have separate analog and digital ground pins. It would be convenient to use a single ground line。V max, and offset drift of 181。 the column address is specified by the column address register. For access from the caption display circuit, the row address of the Display RAM is determined by the vertical position of the character to be displayed. The column address of the Display RAM 第 7 頁(yè) 共 20 頁(yè) is determined by the horizontal position of the character to be displayed. The 32 characters have to be displayed in one line and each character consists of an eightdot horizontal attribute specification code according to the mode used. Italics, flash, underline, and character color are specified in the caption and text modes. Character background color and character color are specified in 16line