整理出租车计价器毕业设计中英文翻译.docx

1、整理出租车计价器毕业设计中英文翻译ABSTRACTIn this paper, a multi-channel taximeter that is able to deal with more than one passenger 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 be

2、en 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. INTRODUCTIONTransporting people in the morning from their homes to

3、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 passengers to different places at the Same time. F

4、or example, a taxicab with four seats may carry four different passengers 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

5、passenger separately. Accordingly, an unfair financial relation was created between the taxicab driver, owner, passengers and the state taxation department.Under these circumstances, taxicab drivers force the passengers to pay more than what they should pay. In some cases passengers had to pay doubl

6、e 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 whic

7、h 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 s

8、uch 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

9、 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

10、 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 passenger simultaneously. I t should be pointed out that by the term passenger we mean a one person or a group of related persons. I t should also be p

11、ointed 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 passengers hiring the taxi

12、cab. 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 Scient

13、ific and Technological Research.2. AN EXPERIMENTAL THREECHANNEL TAXIMETERTheory 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 speedome

14、ter 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 associated with a speed sensor unit.However, our experimental taximeter is not simply a three display readouts. As a matter offact it con

15、tains logic circuits that automatically changes the fare per kilometer of travelling distance or per minutes of waiting time according to the number of passengers 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 t

16、he 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 passengers.A possible components locations is shown in Figure 1

17、.A. Speed Sensor UnitThe main function of this unit is to supply train of pulses whose frequency is proportional to the angular rotation of the wheels. A possible 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 t

18、o 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 cap

19、acitor. 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 switc

20、hing from distance fare to time fare.B. Main Electronic and Display Unit A suggested shape for the main electronic anddisplay unit is shown in Figure 3. The control and display panel contains all controls necessary for operating the taximeter as well as four readout displays. The first channel will

21、give the sum of money required from the first passenger, while the second and third readouts are for the second and third passengers, 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 duri

22、ng 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

23、enabled to be ready for counting the sum of money required from the first, second and third passengers, 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 fo

24、urth 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 CIRCUITThe general block diagram of the main electronic circuit is shown in Figure 4. It consists of five subcircuits d

25、esignated by the symboles CTI up to CT4supporting circuits, these are: The number of passenger 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 Passengers Detection Circuit

26、 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 passengers are hiring the taxicab, respectively. The te

27、rm passenger, here, means one person or a group of related persons. When a passenger 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

28、 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 possible simplified boolean functions that gives minimum number of input

29、s to gates may be obtained from Table I.A possible logical diagram that is based on the above derived expressions 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 CT2As shown from the block diagram of Figure

30、 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 passen

31、gers 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 Eaccording to the level of voltage at input terminale

32、 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 possible circuit diagram that may ve

33、rify 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 CT3As shown in the block diagram, the time scalingcircuit will have four inputs J, K, L and F