【正文】 三、 單元電路的設(shè)計(jì)，參數(shù)計(jì)算和期間選擇 根據(jù)系統(tǒng)的指標(biāo)和功能框圖，明確各部分任務(wù)，進(jìn)行各單元電路的設(shè)計(jì)，參數(shù)計(jì)算和器件選擇。并且對(duì)方案要不斷進(jìn)行可行性和有缺點(diǎn)的分析，最后設(shè)計(jì)出一個(gè)完整框圖。 二、 方案選擇 這一步的工作要求是把系統(tǒng)要完成的任務(wù)分配給若干個(gè)單元電路，并畫出一個(gè)能表示各單元功能的整機(jī)原理框圖 語音復(fù)讀機(jī) —— 單片機(jī)在語音錄放技術(shù)中的應(yīng)用 41 方案選擇的重要任務(wù)是根據(jù)掌握的知識(shí)和資料，針對(duì)系統(tǒng)提出的任務(wù)，要求和條件，完成系統(tǒng)的功能設(shè)計(jì)。t 語音復(fù)讀機(jī) —— 單片機(jī)在語音錄放技術(shù)中的應(yīng)用 40 draw oblique line, mutual together with of cross in addition to using to order to mean at first, according to the demand, can be link online add to note signal or other markings, mean its function or its of the online can mean with the sign, for example the power supply in period generally marks the number of power supply electric voltage and the ground line means with the sign(┴ ). Whether electric circuit of design can satisfy a design request, have to also pass a construction or not adjust to try to carry on a verification. 電子電路的設(shè)計(jì) 設(shè)計(jì)一個(gè)電子電路系統(tǒng)時(shí)，首先必須明確系統(tǒng)的設(shè)計(jì)任務(wù)，根據(jù)任務(wù)進(jìn)行方 案選擇，然后對(duì)方案中的各個(gè)部分進(jìn)行單元的設(shè)計(jì)，參數(shù)計(jì)算和器件選擇，最后將各個(gè)部分連接在一起，畫出一個(gè)符合設(shè)計(jì)要求的完整的系統(tǒng)電路圖。 語音復(fù)讀機(jī) —— 單片機(jī)在語音錄放技術(shù)中的應(yīng)用 35 (3) the parameter of electric resistance and electric capacity should choose a calculation value the mark of the neighborhood to call a value. 3. The spare part choose (1) the ponent choose The electric resistance and electric capacity category is much, electric resistance and electric capacity of the exactitude choice are very different electric circuit requests to be different also to the electric resistance and the electric capacity function and the electric leakage which has solution electric circuit to the electric capacity has very strict request, also some electric circuits are to the electric resistance, and function and capacity of electric capacity have very high example filter in mon use and big capacity(100 uF ～ 3000 uF) aluminum electrolysis electric capacity in an electric circuit, for filter out the high Pin usually still needs to merge small capacity( uF ～ uF) porcelain a slice electric permit a ponent according to choice function and the parameter suitable of the request of electric circuit while design, 語音復(fù)讀機(jī) —— 單片機(jī)在語音錄放技術(shù)中的應(yīng)用 36 and want to notice an achievement to consume, capacity, frequency with bear to press whether scope satisfies a request or not. (2) the cent sign the choice of ponent Cent sign a ponent to include diode,triode,transistor, field effect tube, only give or get an electric shock two(three) poles tube etc..Carry on a choice respectively according to its use. The period category of choice is different and the regulation is also example choice crystal triode transistor, first notice is to choose a NPN type or a PNP type tube, is Gao Pin2 Guan3 or a low frequency tube, is a big power tube or small power tube, and notice the parameter PCM, ICM, BVCEO, ICBO, β of pipe, whether T and β satisfies an electric circuit design the request of the index sign or not, high Pin work, request T=(5~10), is work frequency. (3) the integrated circuit choose Because the integrated circuit can carry out a lot of unit electric circuits the whole function of machine electric circuit even, so choose to design unit electric circuit with 語音復(fù)讀機(jī) —— 單片機(jī)在語音錄放技術(shù)中的應(yīng)用 37 the integrated circuit convenient and vivid with total electric circuit, it not only make the system physical volume contract, and function credibility, easy to adjust to try and make use of, rather popular while designing electric circuit. The integrated circuit imitates integrated circuit and numerical integrated circuit home and abroad already the born be a great deal of integrated circuit, the model number, principle, function of its spare part, the characteristic can check concerning the manual. The integrated circuit of choice not only want to carry out a design a project on the function and the characteristic, and want to satisfy achievement consume, electric voltage, speed, price etc. various of request. Four. The electric circuit diagram draw In order to mean the whole machine electric circuit of the design and the conjunction of each unit electric circuit relation in detail, design need to draw plete electric circuit diagram. Electric circuit diagram usually is at system frame diagram, the design, parameter calculation and spare part 語音復(fù)讀機(jī) —— 單片機(jī)在語音錄放技術(shù)中的應(yīng)用 38 of the unit electric circuit choose of foundation up draw of, it is a construction and adjust to try and maintain of notice once what time while drawing electric circuit diagram: (1) the layout be reasonable and arrange even, the picture is clear, easy to see diagram, be advantageous to the prehension and reading toward the diagram. Sometimes a total electric circuit from several part constitute, should as far as possible chase total electric circuit picture on a piece of diagram paper while the electric circuit is more plicated, need to draw a few diagrams, then should draw main electric circuit on the same piece of diagram paper, two some more independent with next in importance of the part draw on another diagram paper, and marking in doing the break of diagram a people39。Flap to concuss electric resistance in machine, electric capacity, flap to concuss frequency etc. the calculation of the good prehension electric circuit of work principle, the exactitude makes use of calculation formula and the calculating parameter then can satisfy a design a request. When the parameter pute, the same of electric circuit may have a few datas, the attention choose a function that can plete an electric circuit design a request, the ability real viable parameter in the fulfillment. Should notice the following problem while puting electric circuit parameter: (1) dollar the work electric current, electric voltage of the spare part, frequency and achievement consume etc. parameter in res