毕业论文准备
ABSTRACT In this paper, a multi-channel taximeter that is able to deal with more than one paenger simultaneously is proposed.In order to demonstrate the theory of operation of the proposed system, a complete design for an experimental three-channel taximeter (whose prototype has been built under grant from the Egyptian Academy for Scientific and Technological Research) is presented.System location, outline, block diagrams as well as detailed circuit diagrams for the experimental taximeter are also included.1.INTRODUCTION Transporting people in the morning from their homes to their works and back in the afternoon has become a big problem in big cities especially in undeveloped countries.As a partial solution of this problem, the authorities in some countries had, unofficially, left the taxicab drivers to carry different paengers to different places at the Same time.For example, a taxicab with four seats may carry four different paengers without any relation between them except that their way of travelling is the same.Accordingly, it has become very difficult to rely on the present conventional single-channel taximeter to determine the fare required from each paenger separately.Accordingly, an unfair financial relation was created between the taxicab driver, owner, paengers and the state taxation department.Under these circumstances, taxicab drivers force the paengers to pay more than what they should pay.In some cases paengers had to pay double fare they should pay.With the present conventional single-channel taximeter, taxicab owners are not able to determine the daily income of their taxicab.In some cases (a taxicab with four seats) they may only get one quarter of the income of the taxicab (collected by the taxicab driver).From which they should pay the salary of the taxicab driver as well as the cost of fuel, minor and major repairs in addition to the car depreciation.As a matter of fact the position of the taxicab owners is not so bad as it seems.A general agreement has been reached between the taxicab drivers and owners such that the drivers should guarantee a fixed daily income to the owners as well as the paying for the cost of fuel as well as the minor repaires.Even though the taxicab drivers still share the large portion ofthe income of the taxicab.Also with the presence of the single-channel taximeter, it has become very difficult for the state taxation department to know the yearly income of the taxicab and accordingly it has become very difficult to estimate the taxes to be paid by the taxicab owners.In order to face this problem, the state taxation department had to impose a fixed estimated taxes for each seat of the taxicab whatever the income of the taxicab.In this paper, we introduced a multichannel taximeter that can deal with more than one paenger simultaneously.I t should be pointed out that by the term paenger we mean a one person or a group of related persons.I t should also be pointed out that our proposed multi-channel taximeter is not, simply, a multi display readouts.As a matter of fact it contains logic circuits that automatically changes the fare per killometer of travelling distance or per minutes of \'waiting time according to the number of paengers hiring the taxicab.In the following part and as an example, we will present a complete design for a three-channel taximeter.Block diagrams as well as detailed circuit diagrams of the experimental three-channel taximeter are also included.A prototype has been built under grant from the Egyptian Academy for Scientific and Technological Research.2.AN EXPERIMENTAL THREECHANNEL TAXIMETER Theory of operation of our experimental device to work as an electronic digital taximeter is based on t h e fact thathe speedometer cable rotates one revolution for each meter of travelling distance.Accordingly, if the speedometer cable is coupled with a speed sensor that generates a single pulse for each meter of travelling distance, then our taximeter could be three up counter modules aociated with a speed sensor unit.However, our experimental taximeter is not simply a three display readouts.As a matter offact it contains logic circuits that automatically changes the fare per kilometer of travelling distance or per minutes of waiting time according to the number of paengers hiring the taxicab.The device may be splitted into two main parts: The first is the speed sensor unit which may be located anywhere in the taxicab such that an easy coupling to the speedometer cable can be achieved.The second unit contains the main electronic circuit, the displayand control panel.The unit should be located somewhere in front of both the driver and the paengers.A poible components locations is shown in Figure 1.A.Speed Sensor Unit The main function of this unit is to supply train of pulses whose frequency is proportional to the angular rotation of the wheels.A poible form of a speed sensor is shown in Figure 2.If may consist of a tj.pica1 permanent magnet sine wave generator with its output connected to a pulse shapping circuit (two general purpose silicon diodes, 1K ohms resistor and a schmit trigger inverter).In order to find some way to detect the movement of the taxicab, the output of the sine wave generator is rectified through a general purpose silicon diode Dl then smoothed by a 1000 F capacitor.The output voltage at terminal Q is then limited to the value of 4.7 volts by using a Ik ohms resistor as well as a zener diode ZD.The level of the voltage at terminal Q would be high whenever the taxicab is moving and will be zero otherwise.This voltage can be used for the automatic switching from distance fare to time fare.B.Main Electronic and Display Unit A suggested shape for the main electronic and display unit is shown in Figure 3.The control and display panel contains all \' controls neceary for operating the taximeter as well as four readout displays.The first channel will give the sum of money required from the first paenger, while the second and third readouts are for the second and third paengers, respectively.The fourth readout will give the total income of the taxicab.The contents of the last readout should be nonvolatile and be able to be retained even during parking the taxicab.The channel rotary selector switchs 1 , 2 and 3 have fully clockwise/anticlockwise positions.In the fully anticlockwise position, the counter of the corresponding readout is blancked and disabled.In the fully clockwise position, the counter is unblanked, cleared to zero and enabled to be ready for counting the sum of money required from the first, second and third paengers, respectively.Pushing the total sum pushbutton 4 unblanks the fourth readout enabling any person to retain the readout corresponding to the total income.After the release of the pushbutton, the fourth readout will be blanked again.This unit also contains the main electronic circuit which will be fully described in the following section.3.DESCRIBTION OF THE MAIN ELECTRONIC CIRCUIT The general block diagram of the main electronic circuit is shown in Figure 4.It consists of five subcircuits designated by the symboles CTI up to CT4supporting circuits, these are: The number of paenger deticition circuit CTI, travelling distance scaling circuit CT2, waiting time scaling circuit CT3, circuit CT4 which generates clock pulses for the display circuit.A.Number of Paengers Detection Circuit CT1 As shown from the general block diagram, the circuit CTI has three inputs I, 2 and 3 as well as three outputs J, K and L.The function of the circuit is to supply a high level voltage at terminals J, K or L if and only if one, two or three paengers are hiring the taxicab, respectively.The term paenger, here, means one person or a group of related persons.When a paenger is getting into the cab, we simply turn on a free readout display by turning the corresponding rotary selector switch to a fully clockwise direction.This will automatically disconnect the corresponding terminal I, 2 or 3 from ground.The logical relation between various input terminals I, 2 and 3 and the output terminals J, K and L is shown in Table 1.As a combinational circuit we start the design by deriving a set of boolean functions.A poible simplified boolean functions that gives minimum number of inputs to gates may be obtained from Table I.A poible logical diagram that is based on the above derived expreions is shown in Figure 5.It consists of two inverters, four 2-input AND, to3-input AND two 3-input OR gates B.Tavelling Distance Scaling Circuit CT2 As shown from the block diagram of Figure 4, the circuit CT2 has four input J, K, L and E and one output M.The function of the circuit is to supply a single pulse at the output M for a certain number of pulses generated at the output of the speed sensor (certain number of meters travelled by the taxicab), according to the number of paengers hiring the car.A suggested fare per kilometer of travelling distance is shown in colomn two of Table 2.the circuit, in this case, should supply a single pulse at the output M for every 100, 125 or 143 pulses generated at the input terminal E according to the level of voltage at input terminale 3, K or L, respectively.Our circuit could be, as shown in Figure 5, three decade counters, connected as a three digit frequency divider whose dividing ratios 100, 125 and 143 are automatically selected by the voltage level at terminals J, K and L, respectively.A poible circuit diagram that may verify the above function is shown in Figure 6.It consists of three decade counters type 7490, one BCD-to decimal decoder type 7445, three 4-input AND, one 3-input ANDone 2-input AND two 3-input OR gates.
C.Time Scaling Circuit CT3 As shown in the block diagram, the time scalingcircuit will have four inputs J, K, L and F and one output N.The function of this circuit and accordingto colomn three of Table 2 (fare per 2 minuts of waiting time) is to supply a single pulse at the output N for every 120, 240 or 360 pulses supplied at the input terminal F from the I Hz clock according to level of voltage at inputs J, K and L, respectively.Time scaling circuit would be similar to the distance scaling circuit but with different diving ratios.A Poible circuit diagram is shown in figure 7.It consists, in this case, of three decade counter type 7490, two 3-input AND, one 5-input AND, one 2-input AND one 3-input OR gates.
D.Circuit CT4 Which Generates Clock Pulses for Display Circuit The function of this circuit is to supply one, two or three pulses at the output terminal R for each pulse generated at any of the terminals N or M, according to the voltage level at the input terminals J, K or L, respectively.The output P will receive a pulse for each pulse generated at any of the input terminals N or M.This function can be performed by the circuit shown in Figure 8, it consists of one ripple counter type 7493, one half of a dual JK masterslave flip-flops circuit type 7476, three inverters, three 2-input AND, one 3-input AND, one 2-input OR and one 3-input OR gates.When a pulse is generated at either input terminals N or M, a high level voltage will be generated at the output Q of the flip-flop.This will g a t e t h e I Khz signal to be connected to the input A of the ripple counter as well as to the output terminal R.When one, two or three pulses are counted by the ripple counter, according to the level of voltage at the input terminals J, K and L, respectively, a high is generated to reset the counter and change the state of the flip-flopsuch that Q becomes low.Hence, the 1 KHz signal is disabled to reach the outputerminal R or the input A of the ripple counter.In order to ensure the proper function of the circuit, the flip-flop should be cleared whenever a new channel is operated.This has been achieved by the input 5 and will be explained later when describing the function of the channels rotary selector switchs.
E.Display Circuit As shown in Figure 2, the display panel would contain three 4-digit displays that give the sum of money required from each paenger separately as well as a one six-digit display that gives the total income of the taxicab.A poible wiring diagram for the display circuit is shown in Figure 9.Rotating any of the rotary selector switches to fully clockwise direction will supply the corresponding display by5 volts through terminals 1, 2 and 3, respectively.The corresponding display will be unblanked by supplying a low level of voltage through terminals A, C and G, respectively.Keeping terminals 8, D and H, respectively, at low level will keep them reset to zero.The corresponding display is then enabled by removing the low voltage from terminals B, D, and H, respectively, to be ready for counting the sum of money required from the corresponding paenger starting from zero.The counting pulses for these three displays are supplied through terminal P.The total sum display will be enabled whenever any of the three displays is enabled (this is done by a 3-input OR gate as shown in Figure 8).Retaining the contents of the last display will be done by unblanking it by supplying a low level of voltage to terminal I as shown in Figure 10 b.
F.Changing Over Between Time and Distance Fares In the following part, two different methods for changing over between time andistance fares are suggested: The first is to switch to time fare whenever the distance fare is le than the time fare.Hence, a simple look to fares table (Table 2) can show that time fare should be used whenever the taxicab moves with speed le than 50 m/min.A poible circuit that can perform this switching action is shown in Figure IO c.It contains one rpm limit switch and a one inverter as well as two 2-input AND gates.The contacts of the limit switch are normally closed and will be opened whenever the angular speed of the speedometer cablexceeds 50 rmp.The second alternation is to connect the input of the inverter in Figure 10 c.to the output terminal Q of the speedometer circuit, Figure 2.In this case, the switching into time fare will be done whenever the taxicab is at stand still.
G.Function of the Rotary Selector Switches The voltage levels that should be supplied by the terminals of the rotary selector switches in order to ensure proper operation by the electronic circuit are given in Table 3.Connection of three rotary selector switches each witb four decks of five poles each, that satisfy the logic function of Table 3, is shown in Figure 10 a.Rotating any of the three switches into fully clockwise direction will pa through five positions.The function of the rotary selector switches can be described starting from the first position paing through variousteps until reaching the final position as follows: Initial position: In this position a low voltage level is applied to terminals I, 2 and 3, this will disconnect the 5 volts supply from the three first displays, set the three inputs of the number of paenger detection circuit CTI to low level.A low voltage level is applied to terminals 8, D and H, this is to ensure that the total income display is disabled.Voltage levels at terminals A, C, G and S are at no care condition.Step I: Rotating any of the rotary selector switches one step toward clockwise direction will supply 5 volts to the corresponding display, provides a high level voltage at terminals 1, 2 or 3 indicating that one paenger have entered the taxicab.A high level voltage should be applied to terminals A, C or G in order to ensure that the corresponding display is still blanked.Other terminals B, D, H and S are kept unchanged.Step 2: Rotating the rotary selector switch one step further, will change the state of voltages at terminal A, C or G to be at low level and unblanks the corresponding display.States of voltages at terminals I, 2, 3 and S are remained unchanged.Terminals B, D and H should be remained at low level to ensure that the corresponding readout is cleared to zero while unblanking the display.
二、中文翻译
摘要
本文提出了一种出租车多通道计价的方案，能同时处理一个以上乘客的情形。 为了从理论上说明本方案，提出了一个实验上的三通道型的士的完整设计（其原型是根据埃及科学和技术研究学院的研究而建成得）。
1 .导言
在不发达的国家，早上把人们从他们家送到工作的地方，然后下午送回来已成为一个大问题，尤其是在大城市。
作为解决这个问题的一个部分，在某些国家出租车用来解决这个问题，送人们从一个地方到另外一个地方。 例如，出租车的四个席位可携带四个不同的没有任何关系的乘客，除了他们的路线是相同的。
因此，依靠目前的传统的单车道计价以确定所需的票价，把每个乘客的计费分开，这已成为一个非常困难的问题。因此，在出租车司机， 车主，乘客和国家税务部门之间存在着不公平的财政关系。
在这种情况下，出租车司机强迫乘客支付多于他们所应付的。在某些情况下乘客支付了他们应付车费的双倍。
本常规单频道计程车，出租车司机不能够确定出租车日常收入。 在某些情况下（出租车的4个席位） ，他们可能只有出租车四分之一的收入 （ 大部分的出租车司机）。从这些支付工资的出租车司机以及作为燃料费用外，还要维修以及汽车折旧等费用。事实上，出租车业主并非似乎如此糟糕 。一项在出租车司机和车主之间的协议已经达成，司机应保证每天固定收入，以及向业主支付燃料以及维修的费用。即使如此，还是有的出租车司机的很大一部分份额之收入的出租车。现在还存在的单声道计价，已经变得非常，国家税务部门也知道这种困难 每年估计出租车业主的收入支出，以及应支付的税务也很困难。
为了应对这一问题，国家税务部已实行固定估计税，每个座位的出租车不论收入。在本文中，我们介绍了多通道的士计程表，可处理超过一名乘客同时进行的情况。我应该指出，我所说的长期旅客指一个人或一组相关的人。我同时也应指出，我们提出的多渠道的计价，不是简单地说，一个多显示读数。作为一个先进的事项，事实上它包含逻辑电路，可以自动计算变化的车费以及每公里行走距离或每分钟的候车时间按照乘客人数雇用出租车。 在下面的部分，我举出一个例子，我们将介绍一个完整的三通道计价。 框图以及详细的电路图，实验三通道计价功能也包括在内。原型下已建成 埃及赠款科学学院 和技术研究。
2 .实验THREECHANNEL
出租车计价器理论的运作我们的实验装置从事电子数字计价依据。事实上速度电缆旋转1 圈的每米距离行驶。因此，如果车速电缆耦合与速度传感器，产生一个单脉冲每平方米的旅行距离，那么，我们的的士可以三倍于反模块相与速度传感器的单位。然而，我们的实验是计价而不仅仅是只显示三个读数。事实上，它包含逻辑电路，可以根据每公里的行驶距离或每分钟等候时间按照乘客人数雇用出租车来自动改变车费。该装置可能会分成两个主要部分组成：第一是速度传感器，这个传感器可位于任何地方，在出租车内进行这样一个简单的耦合车速电缆是可以实现的。
单位包含了主要的电子电路，显示器以及控制面板。该单位应位于前排的司机和乘客之间。
A． 速度传感器
其主要职能是本单位提供脉冲的培训，这个脉冲的频率会于旋转角度相适合。一种可能的形式一个速度传感器。如果可以包含正弦波发生器的输出连接到脉冲整形电路的永磁器件（2通用芯片二极管，1000欧姆的电阻和施密特触发逆变器） 。
为了找到某种方式来检测出租车的运动，正弦波发生器的输出是纠正通过一个通用的硅二极管延胡索乙然后平滑的1000年F电容。那个输出电压在终端Q是当时限于价值4.7伏特用益欧姆的电阻以及一个齐纳二极管ZD 。出租车的终端电压在终端Q将高电压降为零。这电压可作为改变出租车从距离计费到时间计费方式的开关电压。
主要的电子和显示单元
一个建议是主要形式的电子和显示单元。控制和显示器面板包含所有\'控制所必需的经营的士以及四个可读显示器。第一频道将给出从第一乘客，第二乘客，第三乘客分别应付的费用，第四个会给出总收入给予出租车。最后读出的数据会包括停车的费用等等费用。频道选择器开关1，第2和第3个，按顺时针/逆时针的立场。在充分逆时针的立场，反相应的读出是未标明和残疾人。以顺时针方向则是未定义的，清除为零，对于第一第二第三的乘客分别计费。第四号推进总钮第四次读出，使任何人保留读出相应的总收入。经过释放按钮，第四次读出将再次保留。这个单位还包含主要电子电路将在下一节充分描述。 描述的主要电子电路
它由五个部分指定的电脑符号与电话系统整合成为4个支撑电路，它们是：判断乘客数量电路CT1，旅行距离电路CT2，等待时间电路CT3，时钟脉冲显示电路CT4。
乘客人数检测电路CT1如图所示的一般框图，该电路电脑与电话系统整合有三个输出：1，2和3相对应于三个输出J ，K和L。
这个循环电路函数包含高电压的终端 J，K或L，如果有1个或者2，3个乘客分别租用出租车。这个组里的任意乘客都是一组相关的人。当一个乘客进入出租车后，我们只是表示这样一种情况，自由读出显示在谈到相应的旋转选择开关，以一个完全顺时针方向。 这将自动断开相应的终端1，2或3个从地面。逻辑关系各种输入端子之间第1，第2和第3个输出端J，K和L是列于表1 。 作为一个组合电路，我们开始设计产生了一系列布尔函数。
一种可能的逻辑图的基础上，它包括两个变频器，4个2输入和3输入以及2个3输入或门。B.行驶距离标量环路CT2 ，电路CT2有4个输入J，K，L及E和1个输出M，输出功能的电路是供应单脉冲的输出M的某一些脉冲产生的输出的速度传感器（出租车行驶了一定得距离），根据乘客的人数租用的汽车。我们建议票价按每公里行驶距离显示在两个表格2里面。
表2 这个环路，在这种情况下，应提供单脉冲的输出M的每100，125或143脉冲所产生的输入端根据级别的电压输入终端3，K或L。
我们的电路按图5显示，三个十年的计数器，作为一个三位数分频器的分比率100 ，125和143个自动选定的电压一级终端J ，K和L分别。一种可能的线路图可被验证，它包括三个十年的计数器7490，一个声BCD -以杜威解码器输入7445，3个4输入和1个3输入以及1个2输入和2个3输入或门。
时间缩放电路CT3.时间缩放电路含有4个输入端 J ，K ，L及F和一个输出端N，这个电路的函数根据表格2的意思（车费每2分钟的等待时间）是在J ， K和L分别供应单脉冲到输出端N时，提供单脉冲的输出N。时间缩放电路将类似于距离标量环路，但是有不同的行驶比率。它包括3个十进制计数器7490 ，2个3输入与门和一个5输入与门，1个2输入与门和一个3输入或门。
电路产生时钟脉冲的显示电路CT4 这条电路的作用根据电压电平在输入终端J、K或者L，分别供应1，2或者脉冲在每脉冲的输出终端R引起在任何终端N或M。无论输入端N或者M中的谁发送脉冲，都只有一个脉冲能被输出端P接收。它由一个反向计数器7493构成 ，其中一半是双JK主从触发器电路，型号为7476，包括三个变频器，三个2输入与门，一个3输入与门，1 2输入或门以及一个3输入或门。当脉冲引起在输入的终端N或M，触发器的输入Q上将产生高级电压。这个门信号将被连接到计数器的输入A并且连接到输出终端R。当第一，第二或第三个脉冲由涟波计数器开始计数，J,K,L端会分别根据电压的大小来使产生重置或者翻转来改变状态，然后Q端变为输出低电压。因此，1 KHz信号没有能力到达输出端R或是计数器的输入端A。为了确保电路的函数准确无误，当切换到新频道时，触发器要清零。对于功能选择开关旋转渠道的描述，稍后会以一个成功的5输入门函数来解释。
显示电路
该显示面板将包含三个4位数显示器，这样可以给出每个乘客应付车费的总和，一个六位数显示器可以给出出租车的总收入。以顺时针方向旋转所选择的开关将提供相应的显示，这可以通过5伏电压来分别控制1，第2和3终端。对应的显示通过供应低级电压通过终端A、C和G，分别。保持终端D和H在低级状态下重置为零对应的显示分别通过终端B,D,H而改变低压状态，并准备好从对应的乘客那里计算出相应的计数款额，计数脉冲这三个显示器通过终端提供总额。计数器还将通过终端P为3个显示器提供脉冲只要这三个显示器中任意一个是正常的，那么总额将被显示出来。
时间和距离变化时车费的改变
在下面的部分，两种不同的方法使得时间和距离改变从而导致车费发生变化，有如下建议：首先是当以路程计价的费用低于以时间计费的费用时，采用时间计费。从此，一个简单的票价表显示当出租车移动速度小于50米/分时应该采用时间计费方式。一种可能的电路可以执行此开关行动如图10c，它包含一个转速限位开关和一个反转器以及两个2输入与门。接触的限位开关通常是封闭，只有当角速度超过50RMP的时候才会打开。第二个改变将中断连接到图10C的输入端，输出端Q连接速度的电路。在这种情况下，只要出租车的状态保持静止，那么计费开关就会处于关闭状态 。
功能选择旋转开关
功能选择开关旋转的电压应提供的该终端的旋转选择开关，以确保正常运行的电子电路列于表3。每5个杆就有4个板连接着3个旋转选择开关，每个符合逻辑功能表3，旋转任何三个切换到完全顺时针方向将通过5个职位。功能的旋转选择开关可以说是从第一的位置通过直到达到最后的立场如下：
初始位置：在这个位置上的低电压电平适用于第一第二和第三终端，浙江断开来自三个中一个显示器的5伏特电压供应，设置三个显示器，乘客检测电路并与电路系统整合到较低的水平。终端D,H采用低电压，这是为了确保显示的总收入选项已被禁用。
步骤1：以顺时针方向旋转任何旋转选择开关一格将提供5伏特电压到相应的显示，提供一个高等级的电压终端1，2或3，这表明一名乘客已经进入了出租车。终端C，G应为高电平，以确保相应的显示仍然是笼罩。其他端口，如D，H端口保持不变。
步骤2：旋转旋转选择开关1，然后将在终端A，C或G上改变电压使其处于低电压状态， 并会产生相应的显示。终端1，2，3以及S上的电压状态保持不变。终端B，D和H应保持在较低水平，以确保当显示为无数据时相应的读出清除为零。
