Ch23 Principles of Electronic Signal Processing
10.Technician A says logic gates can only process binary data. Technician B says that binary, hexadecimal, and alphabetic information are outputs from an ECU. Who is correct? A. Technician A B. Technician B C. Both Technician A and Technician B D. Neither Technician A nor Technician B
A , p547, Logic gates are constructed from transistors arranged to process two or more digital signals using a set of rules or logic. At an operational level, gates are essentially switches with a voltage signal representing 1 as on, and 0 or off represented by the absence of voltage.
Processing collects sensor data and determines outputs based on
A set of instructions or program software.
10. Consider a electro hydraulic pressure regulator operating with a fixed frequency of 0.5 seconds. The duty cycle is 50%. How long is the pressure regulator energized? A. 0.5 seconds B. 0.25 seconds C. 0.75 seconds D. 50 milliseconds
B , p546, Duty cycle is measured as a percentage - on time versus off time. Fixed frequency times duty cycle equals energized length.
7. What type of signal is produced by a toggle switch? A. Analog B. Digital C. PWM D. Hybrid analog-digital
B ; p540, 544 Digital signals do not vary in voltage, frequency, or amplitude. Instead, they are electrical signals that represent data in discrete, finite values. Vehicle control system process information electronically using digital signals represented by binary code. This means all information, whether analog, alphabetic, or hexadecimal, is converted into 1's and 0's.
Logic gates process digital signals using binary code. Hexadecimal numbers are
Converted from binary digits to shorten the length of a binary word or number.
Because electronic processing units can only handle binary digital data, analog signals are
Converted to digital signals by special circuits known as buffers or AD converters.
Three types of electrical signals commonly used as
Either inputs or outputs in electronic engine control applications are analog, digital, and PWM.
An analog signal is an
Electric current that is proportional to a another continuously changing variable.
The use of electronic engine and vehicle control systems provides for
Enhanced vehicle and occupant safety and security.
Frequency is the number of events or cycles that occur in a period. The unit of measure for frequency is
Hertz (Hz), which is the number of cycles per second.
Electromagnetic interference is a major electrical system problem caused by the
Induction of unwanted electrical signals into current-sensitive vehicle circuits. Four types of methods are used to introduce EMI into a vehicle and a unique method for each type of EMI prevents it form disrupting vehicle operation.
Electronic systems using microcontroller-based controls provide operational capabilities far exceeding any mechanical system. The dominance and sophistication of electronic control makes skill development related to servicing this technology
One of the most important priorities for successful technicians.
Sensing functions collect data about
Operational conditions or the state of a device by measuring some value, such as temperature, position, speed, pressure or flow.
Ladder logic is used by PLC controllers to process
Output signals according to switch and sensor inputs.
An electrical signal that shares similar characteristics with both a digital and analog signal is the
PWM electrical signal. PWM refers to a signal that varies in on and off time. A PWM signal is typically measured in milliseconds.
Duty cycle is another unit of measurement for PWM signals, and it refers to the
Percentage of time a PWM signal is on versus the time it is off. Duty cycle is commonly used to measure the time a signal is applied to an output device operating at a fixed frequency, whereas pulse width measures a signal applied to devices operating at a varying frequency interval.
Serial data is used to transmit information from one electronic module to another. On-board data networks
Share information and control vehicle operation using serial data.
3.Technician A says telematics uses specialized telecommunication applications for long-distance transmission of information to and from a vehicle. Technician B says that telematics is not capable of transmitting information on fault codes. Who is correct? A. Technician A B. Technician B C. Both Technician A and Technician B D. Neither Technician A nor Technician B
A , p536, Messages are sent back and forth between the vehicle and a central dispatch location using radio-satellite or cellular-based vehicle communications.
9. Technician A says that serial data is used to exchange data between electronic service tools and an ECU. Technician B says that baud rate of serial data refers to the number of data bits transmitted per minute. Who is correct? A. Technician A B. Technician B C. Both Technician A and Technician B D. Neither Technician A nor Technician B
A , p542, The relevance of the network and serial data to technicians is that service tools connected to the diagnostic data link connector read messages and send commands using serial data. Baud rate is the number of data bits transmitted per second.
8.Technician A says that a missing ground strap on a chassis with air ride suspension could potentially produce a type of EMI interference. Technician B says that EMI is only caused by strong radio signals from a cell phone of CB radio. Who is correct? A. Technician A B. Technician B C. Both Technician A and Technician B D. Neither Technician A nor Technician B
A , p550, EMI is created whenever current flows in a conductor is disrupted by an external force. EMI can be broken down further to radio frequency interference where EMI is induced from radio signals.
5. Which of the following diagnostic strategies is used by technicians during off-board diagnostics? A. Performing pinpoint tests of circuits and components B. Retrieving fault codes C. Identification of out-of-range voltage codes D. Verifying correct system functionality
A ; p537, Electronic service tools assist the technicians to perform off-board diagnostics or moreover, perform pinpoint checks to precisely identify system faults.
Service technicians, particularly in fleet operations using medium-heavy-duty engines, can access
A wealth of diagnostic and service information much faster and with more precise detail than before.
1. Which of the following was the earliest control system to switch from mechanical to electronic control? A transmissions B. Diesel engines C. Anti-lock braking D. Climate control
B , p534, Diesel engines were the first commercial vehicle systems transformed by electronic controls. Diesel engines with only mechanical controls had reached their limit of efficiency, so the next logical step was to apply electronic controls already used on gasoline engines.
5.Technician A says that a PWM signal appears as a continuous wave when displayed on a graphing meter or oscilloscope. Technician B says that a PWM signal appears rectangular or square-shaped when graphed. Who is correct? A. Technician A B. Technician B C. Both Technician A and Technician B D. Neither Technician A nor Technician B
B , p546, 544. The measurement units for a PWM signal can also be a duty cycle. Duty cycle is expressed as a percentage of on time versus off time. Displayed on a graphing meter, PWM signal is shown in discrete waves, either on or off, and varies its length of being on or off.
6. What type of electrical signal is viewed using a sweeping needle of a voltmeter? A. digital B. Analog C. PWM D. Radio wave
B ; p540, The numerical display for an electrical measurement is represented as a fixed number or digit. In contrast, an analog meter measures the same electrical value using a sweeping needle on a scale.
9. Which of the following would most likely be the cause of conductive-coupling EMI? A. A missing body panel ground strap B. A defective alternator C. Wires without conductive EMI shielding D. Self-induction
B, p551; Conductive coupling interference is transmitted into a circuit by connecting a sensitive electrical circuit to a source of interference. An example is an alternator with AC voltage ripple that is superimposed over the chassis DC. The AC and frequent change of voltage is transmitted throughout the electrical system connected to the alternator output cable. It's noticeable when the AC ripple causes the speedometer or tachometer to bounce or fluctuate at particular speeds coinciding with the frequency of the AC ripple. Random unexpected fault codes are set in the ABS and other control systems. Ripple can interfere with signals transmitted by the CAN and to the engine sensors or ECU and cause unstable operation.
Logic gate are the
Basic building blocks of electronic circuits used in microcontrollers and processors. Logic gates are arranged together to perform mathematical computations and process software logic.
Binary code is an example of a digital signal. "Bit" is a shortened term for
Binary digit. This is the smallest piece of digital or binary information and is represented by a single 0 or 1. A byte is a combination of eight bits.
Electronic control systems can be
Broken into three major divisions: sensing, processing, and output or actuation.
6.Technician A says processing refers to the control system element that collects sensor data and determines outputs based on a set of instructions or program software. Technician B says that calibration data provides the control system with data that is unique or specific to the ECU application. Who is correct? A. Technician A B. Technician B C. Both Technician A and Technician B D. Neither Technician A nor Technician B
C , p537, 538; Processing refers to the control system element that collects sensor data and determines outputs based on a set of instructions or program software. Calibration information is primarily reference data used by algorithms. Calibration information contains unique information for a specific application.
1.Technician A says most vehicle systems now operate with at least some degree of electronic control. Technician B says that using electronic control systems has increased the cost and time involved diagnosing complaints. Who is correct? A. Technician A B. Technician B C. Both Technician A and Technician B D. Neither Technician A nor Technician B
C , p537, p534.
2.Technician A says that electronic signals can transmit information and control electrical devices. Technician B says that only binary information can be processed by microcontrollers built into an electronic control module. Who is correct? A. Technician A B. Technician B C. Both Technician A and Technician B D. Neither Technician A nor Technician B
C , p541, Computers do not use hexadecimal, only binary. Humans read hexadecimal to more readily understand binary. Speed data processed by ECMs is measured in bits.
7.Technician A says serial data is used by ECUs to communicate information. Technician B says serial data transmits information using binary code. Who is correct? A. Technician A B. Technician B C. Both Technician A and Technician B D. Neither Technician A nor Technician B
C , p542. The term, Serial data, originates from the way data is transmitted. It is transmitted in voltage pulses produced in series - one bit after another. A voltage pulse is represented as a square or rectangular digital waveform. Serial data is important because it is used to exchange information from one electronic module to another.
8. Which of the following is most likely an example of hexadecimal number? A. 58 B. 00110101 00111000 C. $003A D. 5x0011
C ; p541,
2. Which of the following reasons best explain the necessity for self-diagnostic capabilities that are built into electronics control systems? A. It enables the use of personal computers, tablets, and cell phones to diagnose problems. B. Service technicians can collect more diagnostic abs service data than before. C. It is too time consuming to trace faults using a multimeter. D. Fault codes can be stored for review.
C p537
Built-in electronic control systems allow vehicles to check the operation of circuits and electrical devices, evaluate the rationality of data, and identify problems as they occur. The presence of faults is
Communicated through the malfunction indicator lamps, electronic service tools, or Windows-based diagnostic software.
4.Technician A says the units for reporting a pulse-width-modulated signal are measured only in milliseconds. Technician B says that a PWM signal is only reported as a percentage or duty cycle. Who is correct? A. Technician A B. Technician B C. Both Technician A and Technician B D. Neither Technician A nor Technician B
D , p544, 546. Pulse width modulation refers to a signal that switches on and off and varies its time. The ratio between the on or off time is variable. The units for measuring a signal pulse width are always expressed in units of time.
4. Which of the following types of signals are only used by telematics? A. Analog signals B. Digital signals C. Pulse-width-modulated signals D. Radio signals
D ; p535, Telematics uses specialized telecommunication applications for long-distance transmission of information to and from a vehicle. Vehicles are equipped with radio-satellite or cellular-based vehicle communications where a technician can remotely monitor any information about the vehicle, engine, or product the vehicle is carrying.
3. Which of the following statements best describes the job of electrical signals? A. They provide the electrical force needed to operate components drawing high amounts of electrical current. B. They are used to operate low current accessories, such as LED lights and illuminated instrument displays. C. They are switched and manipulated using relays, switches, and manual control devices. D. They are produced by electronic circuits to transmit information and control electrical devices.
D ; p538, Electricity can be shaped and manipulated by electronic circuits and specialized electrical devices into unique signals capable of exerting control over electrical components, transmitting complex information, and detecting remote objects while precisely calculating their speed and distance. Electricity can be shaped into language a understood by machines, and even used as a tool to make logical decisions.
The outputs of a system are functions performed in response to
Electrical signals produced by the processor.
In contrast to analog signals, digital signals do not vary in voltage, frequency, or amplitude. Instead, they are
Electrical signals that represent data as binary values, such as on-off, 0 or 1, yes-no, up-down, open-closed, etc.
Diesel engines were the first commercial vehicle systems transformed by
Electronic controls. The immediate benefits of these refinements to power train control include lower engine emissions, improved fuel economy, increased reliability, and enhanced performance.
Programmable software provides flexibility to engines, transmissions, and body accessories to adapt to specific job applications while providing enhanced vehicle productivity, longevity, and driver comfort. Programmable features include
Idle shut-down timers, cruise control, maximum vehicle speed limits, and safety interlocks that prevent the vehicle from moving if a door is open, a boom is raised, or outriggers are extended.
Hexadecimal numbers are not used by
Logic gates or microcontrollers, but only by humans.
Telamatics, a branch of information technology, uses specialized applications for
Long distance transmission of information to and from a vehicle. Messages can be sent back and forth between the vehicle and a central dispatch location.
