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Practice Exam 1

Dec 13, 2014





  • 1. Practice Exam 1

2. 1. EPC Generation 2, after being ratified by the International Organization forStandardization (ISO), will be put into A. ISO 18000 Part 8 B. ISO 18000 Part 6 C C. ISO 18000 Part 5 A D. ISO 19000 Part 1 The 18000 series applies to air-interface management. 18000-1 Part 1Generic Parameters for the Air Interface for Globally Accepted Frequencies 18000-2 Part 2Parameters for Air Interface Communications below 135 kHz 18000-3 Part 3Parameters for Air Interface Communications at 13.56 MHz 18000-4 Part 4Parameters for Air Interface Communications at 2.45 GHz 18000-5 Part 5Parameters for Air Interface Communications at 5.8 GHz (this part has beenwithdrawn) 18000-6 Part 6Parameters for Air Interface Communications at 860 to 960 MHz 18000-7 Part 7Parameters for Air Interface Communications at 433 MHz ISO 18000 part 6A and B specifies the air interface guidelines for passiveRFID in the UHF (900 MHz) band. EPC Class 1 Generation 2 after being ratified by ISO will be established as a part 6C. 3. 2. Define the formula for Effective Radiated Power (ERP). A. ERP = power input + antenna gain in dBd B. ERP = antenna length / power input C. ERP = antenna gain / power input * dBi D. None of the above ERP (dBm) = Power of transmitter (dBm) loss in transmission line (dB) + antenna gain in dBd 4. 3. Which of the following statements is true? A. Thermal transfer uses a special print head that turns label media a dark color. B. Thermal transfer does not use a ribbon. C. Direct thermal uses a ribbon. D. Thermal transfer uses heat to transfer an image from a ribbon to the label media. Answer A is incorrect because that is the method used by direct thermal printing. Answer B is incorrect because the thermal transfer method uses ribbon. Answer C is incorrect because direct thermal does not use a ribbon. 5. 4. Which of the following are true of frequency hopping? A. It can use the spread spectrum transmission method. B. It sometimes needs to listen for a signal before using a channel. C. It reduces the effects of noise and interference in a transmission. D. It allows an interrogator to read multiple frequency tags. Interrogation signals hop between channels within a certain frequency spectrum. In the United States, they can hop between 902 MHz and 928 MHz, and they can be required to listen for a signal before using a channel. There are two types of frequency hopping: spread spectrum and direct sequence spread spectrum. Frequency hopping reduces the effects of interference and noise by not transmitting on the same frequency at the same time.Answer D is incorrect because frequency hopping does not relate to reading tags; it refers to a way interrogators communicate. 6. 5. Which of the following is not an interrogators command? A. Inventory B. Select C. Interrogate D. Access Interrogate is not an interrogator command. There are three basic command operations to manage tag populations. They are Select, Inventory and Access.The Select command is used to determine which groups of tags will respond.The Inventory command is used to identify (singulate) individual tags from a group. The Access command is used after the tags have been singulated and individual commands can now be addressed to those tags. 7. 6. Which of the following is not generally a component of afixed RFID interrogator? A. An oscillator B. A transmitter C. A modulator D. An antenna An antenna is not a component of a fixed interrogator. Fixed interrogators have ports for one or more antennas but generally do not have antennas integrated into them. Handheld interrogators have antennas built into them. Other components of fixed (and handheld) interrogators include a receiver that holds an amplifier and a demodulator, a transmitter that holds a modulator and a power amplifier, an oscillator, a controller/processor, and an input/output port to an antenna. 8. 7. Backscatter refers to what phenomenon? A. Modulated reflection of an interrogators energy B. The range at which the signal from an active tag begins to break up C. The dispersion of interrogators at a site to be certain all tags are read D. The energy received by an interrogator from an active tag UHF and microwave passive tags communicate with an interrogator using passive backscatter (also calledmodulated backscatter ). The interrogator transmits a continuous-wave RF signal into the reading environment. When a tag appears in the area, it receives the signal and modulates (or breaks up) the RF signal into patterns of ones and zeros that define the tags digital data while reflecting it back to the interrogator. Answers B and D are incorrect because backscatter does not apply to active tag technology. Answer C is incorrect because setting up interrogators at a site to ensure all tags are read is called setting up an interrogation zone or creating a sweet spot, and not backscatter. 9. 8. Which of the following are characteristics of semi-passive tags? A. They use a battery to run the microchips circuitry. B. They beacon to the environment. C. They can use inductive coupling to communicate to the interrogator. D. They communicate by drawing power from the interrogator. Semi-passive tags have an onboard power source, and that power source is used to run the tags circuitry. They can use inductive coupling or passive backscatter to communicate with the interrogator, which by definition means that they draw power from the interrogator to do so. They do not beacon or transmit signals to the interrogator.Beaconingis a term that is commonly used when talking about active tags. 10. 9. Which of the following does not affect interrogator interference when multiple interrogators are present? A. The distances between antennas B. The amount of vibration the antennas are subject to C. The power output of the antennas D. The presence of shielding Although vibration is a consideration of the physical site, which still should be taken into account when you are evaluating the site survey, it has minimal if any effect on interference. The radio transmissions from the interrogators antennas may interfere with other interrogators, so much so that the tags are unable to completely understand the information being read or written and the interrogator may misread the tag. The level of interference depends on a number of factors. They include the size of the antennas, the output power of the antennas, the distances between antennas, and the presence (or absence) of shielding. 11. 10. Which of the following functions can RFID printers perform? A. Write information to tags on labels B. Print tag antennas on labels C. Verify tags on labels D. Trigger a divert gate RFID printers/encoders can read, write, and print smart labels. The RFID tags are read, written, and verified inside the printer prior to printing due to the embedded RFID interrogator. In the case of a tag failure, the RFID printers mark the tag (usually print a label with the wordVOID ) and advance to the next one, assuring high reliability in mission-critical applications. RFID printers cannot print tag antennas or chips on labels; therefore, answer B is incorrect. Answer D is incorrect because printers do not trigger divert gates; software does. 12. 11. Which of the following is not antenna polarity? A. Spherical polarity B. Horizontal polarity C. Vertical polarity D. Circular polarity There is no spherical polarity in RFID antennas defined. Answers B, C, and D are incorrect. Polarization can be either circular or linear. Linear polarization is relative to the surface of the earth. Linear polarization can also be either horizontal or vertical. Horizontally polarized signals propagate parallel to the earth, whereas vertically polarized signals propagate perpendicular to the earth. Antennas with circular polarization can receive signals from both the vertical and horizontal planes; however, there is a slight loss of signal strength. 13. 12. Low Frequency (LF) tags operate at what frequency? A. 860960 MHz B. 2.45 GHz C. 120140 KHz D. 13.56 MHz The four primary frequency bands for RFID tags are Low Frequency or LF (120140 KHz) High Frequency or HF (13.56 MHz) Ultra High Frequency or UHF (860960 MHz) Super High Frequency/Microwave (2.45 GHz and above) 14. 13. Which of the following are needed to ensure RFID optimum tag/smart label performance? A. Printer calibration B. Correct label placement on product C. Label tag verification D. All of the above Answer A is correct because printer calibration fulfills the need to set for the correct media length, type, print mode, and sensor values. Answer B is correct because correct label placement on product ensures optimal performance; the polarization, air gaps, and other considerations have to be taken in mind. Answer C is correct because smart label tag verification tests the tags function, and the printer should have a method of exception processing that provides a solution for dealing with bad tags. 15. 14. Which of the following are usually included in a site survey? A. Changes in RFID team and cooperation of management with changes due to RFID implementation B. Determining environmental factors that would affect RFID implementation C. What operational restrictions are in place that would affect RFID equipment placement D. What radio frequency equipment is in place that would interfere with new RFID equipment A physical site survey determines whether the environment is a threat to successful implementation and operation of an RFID system. Answer B is correct because environmental conditions in the site that will possibly affect tags, interrogators, antennas, printers, and so on, are important to understand, as well as whether this equipment will be deployed in an area with extreme temperature, humidity, dirt, and other problematic conditions. Answer C is correct because any operational restrictions affecting the location of in