NEETS MODULE 23 CHAPTER 1 INTRODUCTION TO MAGNETIC RECORDING
Q-1. Why did the early inventors of magnetic recording find it necessary to add a fixed dc bias to theinput signal?
Q-2. How does dc bias added to the input signal correct the distortion in the output signal?
Q-3. Why does adding dc vice ac bias voltage to the input signal result in a poor signal-to-noise ratio(SNR)?
Q-4. What are three advantages of adding an ac bias voltage to the input signal instead of adding afixed dc bias voltage?
Q-5. Why does using ac vice dc bias voltage result in a stronger output signal?
Q-6. What three things are required to perform magnetic recording?
Q-7. What is the meaning of the term recording medium as it pertains to magnetic recording?
Q-8. What are the three functions of the magnetic heads on a magnetic recording device?
NEETS MODULE 23 CHAPTER 2 MAGNETIC TAPE
Q-1. Magnetic tape is made of what three basic materials?
Q-2. Why is plastic magnetic tape used more than metal tape?
Q-3. Which of the two types of magnetic tape is used to record audio and instrumentation type signalsin the VLF to 2.5MHz frequency range?
Q-4. What type of magnetic tape is used to record computer programs and data, and what are theadditional thickness and quality standards for this type of tape?
Q-5. What are four types of tape errors that can degrade a magnetic recording system’s performance?
Q-6. What are signal dropouts, and what are two tape defects that can cause signal dropouts?
Q-7. What is the most common and most serious type of signal dropout?
Q-8. You see a build-up of dust and lint on the take-up reel of a tape recorder. This can cause which ofthe four types of tape errors?
Q-9. What type of tape error causes noise to appear on the tape when no signal should appear? Whatcauses this type of tape error?
Q-10. The multi-track tape recorder in your computer system has a fixed skew error. What does thismean and what is the probable cause?
Q-11. Some tapes you are using may have level errors. What does this mean and what is the cause?
Q-12. What is tape failure?
Q-13. What are four main causes of tape failure?
Q-14. How does normal wear cause tape failure?
Q-15. Accidental damage to magnetic tape is normally caused by the tape recorder itself or by humanoperators of the recorder. What are three frequent causes of such accidental damage?
Q-16. Environmental damage to magnetic tape can occur when the tape is stored in an area thatexceeds what ideal temperature and humidity ranges?
Q-17. What six types of environmental damage can occur to tapes in storage when the idealtemperature and humidity ranges are exceeded?
Q-18. After using a tape that was stored in an area where temperatures exceeded 130º F you noticepieces of oxide sticking to the recorder's tape-transport mechanism, to its magnetic heads, andonto the tape. What is the probable cause of these symptoms?
Q-19. Your activity stores its magnetic tape in an area where the temperature is 100º F. What two typesof environmental damage could occur that would make these tapes unusable?
Q-20. When the relative humidity is below 10%, what happens to magnetic tape and parts of a taperecorder that could cause environmental damage?
Q-21. How does relative humidity over 95% cause excessive tape and head wear?
Q-22. Tape winding errors can cause a deformed tape pack. What are four common types of tape packdeformation?
Q-23. After rewinding a tape onto its supply reel, you examine the tape pack and notice pile-ups of taperesembling the example in figure 2-2. What causes this condition?
Q-24. You notice steps in the tape pack such as those in figure 2-3. What causes this and how does itdamage the magnetic tape?
Q-25. A tape pack is buckled and deformed as shown in figure 2-4. What are three possible causes forthis condition?
Q-26. A tape pack has gaps in the tape winding as shown in figure 2-5. What causes this condition?
Q-27. When winding a tape onto a plastic or metal reel, should the tape ever touch the reel’s flanges?
Q-28. What are two disadvantages of using a recorder’s erase head to erase data recorded on amagnetic tape?
Q-29. What method for erasing magnetic tape is much more effective and reliable than using arecorder’s erase head?
Q-30. When magnetic tapes are ruined, what three factors are normally the cause?
Q-31. What is the correct way to hold a magnetic tape reel?
Q-32. The take-up reel on your recorder is warped. What should you do to/with the reel?
Q-33. If magnetic tape is stored in areas with temperature and humidity extremes, what are three types of tape damage that may occur?
Q-34. List four rules you should follow when storing magnetic tape to protect it from damage.
Q-35. When packaging tape reels or cartridges for shipping, what are four rules you should follow to protect the tape reels from impact and vibration?
NEETS MODULE 23 CHAPTER 3 MAGNETIC TAPE RECORDER HEADS
Q-1. Magnetic tape recorders can have up to three different heads installed. What are the threefunctions performed by a recorder's heads?
Q-2. The way a magnetic head will be used determines how it is constructed. Name three factors thatdetermine the final construction of a magnetic head.
Q-3. What two specifications determine the maximum frequency that a recorder's record andreproduce heads will be able to transfer?
Q-4. Most record and reproduce heads are in one of what three bandwidth categories?
Q-5. Why are record heads always placed before reproduce heads on recorders?
Q-6. A recorder's erase head is always placed in what sequence on the record/reproduce track?
Q-7. What two preventive maintenance actions must you do regularly to increase magnetic head life andto ensure good tape recording and playback?
Q-8. How should you clean your recorder's magnetic heads?
Q-9. What are four sources that can cause magnetic heads to become magnetized?
Q-10. What type of equipment should you use to demagnetize your recorder's magnetic heads?
Q-11. How often should you demagnetize a recorder's magnetic heads?
NEETS MODULE 23 CHAPTER 4 MAGNETIC TAPE RECORDER TRANSPORTS
Q-1. What are the four basic parts of a magnetic tape recorder's tape transport system?
Q-2. What are the three most commonly used tape reeling systems?
Q-3. What are two disadvantages of the take-up control reeling system?
Q-4. What are two advantages of a two-motor reeling system over a take-up control reeling system?
Q-5. What type of reeling system best controls a tape recorder's tape tension during starts and stops?
Q-6. What are the two basic types of tape buffering reeling systems?
Q-7. How do the tape guides on a tape reeling system protect the tape from damage during operation?
Q-8. There are two types of tape transport configurations, open-loop capstan drive and closed-loopcapstan drive. What are two major disadvantages of open-loop capstan drive tape transports?
Q-9. How do closed-loop capstan drive tape transports overcome the disadvantages of the open-loopdrive design?
Q-10. What are the three most common closed-loop capstan drive designs?
Q-11. How do tape transports with differential velocity capstans maintain a constant tape tension in thearea around the magnetic heads?
Q-12. How do dual-motor dual capstan drives maintain a constant tape tension while operating ineither a forward or reverse direction?
Q-13. What are the two critical functions of the capstan speed control part of a magnetic tape transportsystem?
Q-14. Which part of the capstan speed control function monitors the true capstan motor speed?
Q-15. Sometimes it's necessary, but why should you avoid using cotton swabs when cleaning a magnetic tape transport?
Q-16. When cleaning the parts of a tape transport, why should you switch lint-free cloths and swabsoften?
Q-17. What equipment should you use to de-magnetize a magnetic tape transport?
NEETS MODULE 23 CHAPTER 5 MAGNETIC TAPE RECORDER RECORD AND REPRODUCE ELECTRONICS
Q-1. What two types of record and reproduce electronics are used by magnetic tape recorders?
Q-2. The head driver circuit in a tape recorder’s direct record electronics component (figure 5-1)performs what function?
Q-3. The equalization and phase correction circuit in a tape recorder’s direct reproduce electronics(figure 5-2) performs what function?
Q-4. How do FM record electronics differ from AM (direct record) electronics?
Q-5. The head driver circuit of a tape recorder’s FM record electronics (figure 5-4) performs whatfunction?
Q-6. What is the major difference between direct reproduce electronics and FM reproduceelectronics?
NEETS MODULE 23 CHAPTER 6 MAGNETIC TAPE RECORDING SPECIFICATIONS
Q-1. Two tape recorders have signal-to-noise ratios (SNRs) of 25-dB RMS and 35-dB RMSrespectively. Which of the SNRs can record and reproduce the widest range of input signals andwhy?
Q-2. You plan to measure your tape recorder’s SNR. What test equipment will you need?
Q-3. Technical manuals for tape recorders can state the SNR in what three different ways?
Q-4. The frequency-response specification of your tape recorder reads within +/- 3 dB from 150 Hz to150 kHz at 60 ips. What does this mean?
Q-5. While measuring frequency response, as the signal generator approaches the lowest and highestfrequency the recorder can effectively record, the VTVM reading drops to less than - 3 dB. Whatdoes this indicate?
Q-6. List four factors that can degrade the frequency response of magnetic tape recorders.
Q-7. A recorder’s harmonic-distortion specification reads 2% third harmonic of a 100-kHz signal at60 ips. What does this mean?
Q-8. What are three possible causes of even-order harmonics?
Q-9. What number harmonic is the primary harmonic distortion in magnetic tape recorders?
Q-10. When measuring harmonic distortion, you set the signal generator to input a 15-kHz test signal.To what frequency should you set the wave analyzer?
Q-11. How should a tape recorder with good phase response reproduce a complex waveform, such as asquare wave?
Q-12. How could you check the phase response of a tape recorder?
Q-13. What causes flutter in a tape recorder’s output?
Q-14. What causes low-frequency flutter (below 1000 Hz)?
Q-15. What causes high-frequency flutter (above 1000 Hz)?
Q-16. Your recorder’s TBE specification reads " +/- 80 microseconds over a 10 millisecond timeinterval at a tape speed of 60 ips, referenced to a control tone." What does this mean?
Q-17. Why is it important to minimize TBE jitter in magnetic tape recordings where precise timingrelationships exist between two or more signals?
Q-18. The skew specification of your multi-tracked tape recorder reads " +/- 0.20 microsecondsbetween adjacent tracks on the same head stack at 120 ips." What does this mean?
Q-19. How can you minimize fixed skew?
Q-20. When are fixed skew errors most likely to show up?
Q-21. How do worn or sticking tape transport guides cause dynamic skew on a multi-track recorder?
NEETS MODULE 23 CHAPTER 7 DIGITAL MAGNETIC TAPE RECORDING
Q-1. In digital magnetic tape recording, the series of recorded digital pulses can represent what threetypes of data?
Q-2. What three formats are used for digital magnetic tape recording?
Q-3. What format of digital tape recording is normally used to store computer data?
Q-4. What format of digital tape recording takes a serial input stream of data pulses, breaks them up,and records them on more than one data track?
Q-5. What format of digital tape recording is normally used to record instrumentation or telemetrydata?
Q-6. Which of the eight methods for encoding digital data onto magnetic tape is most widely usedbecause it’s accurate, simple, and reliable?
Q-7. Which digital data tape encoding method presets the magnetic tape to all zeros and then recordsdigital ones onto the tape?
Q-8. Which digital data encoding method records a digital one as a positive pulse and a digital (zero)as a negative pulse and returns the tape to neutral between pulses?
Q-9. Which method of digital data encoding does NOT return the tape to neutral between pulses but,instead, saturates the tape positively or negatively as the incoming data changes between zeroand one?
Q-10. What are the four widely used variations of the NRZ encoding method?
Q-11. Which digital data encoding method helps overcome a tape recorder’s low-frequency responseproblems by recording two logic levels for each incoming data bit?
Q-12. Digital magnetic tape recorders used to store and retrieve digital data fall into what threecategories?
Q-13. What category of digital tape recorder is used for recording pulsed square-wave signals with abandwidth of 500 kHz to 2 MHz?
Q-14. What category of digital tape recorder is used to record special signals with a bandwidth of lessthan 500 kHz?
NEETS MODULE 23 CHAPTER 8 MAGNETIC DISK RECORDING
Q1. Floppy disks are manufactured in what three sizes?
Q2. What type of floppy disk is made to store data on both sides of the disk?
Q3. What are the three levels of floppy disk density?
Q4. What is the storage capacity of a 5-1/4" double-sided, high-density floppy disk?
Q5. The floppy disks you are using have a rating of 96 TPI. What does this mean?
Q6. The process of formatting a floppy disk is called what type of sectoring?
Q7. What three components determine the address that locates where on a floppy disk the computerwill store the data?
Q8. Why should you always store floppy disks in their envelopes?
Q9. Why should you never place floppy disks near telephones or other electronic equipments thatgenerate magnetic fields?
Q10. What are the two ways to erase floppy disks?
Q11. What are the three most common sizes of hard disk platters?
Q12. Computers use what two methods to place data on a hard disk?
Q13. Which method for placing data on hard disks divides a hard disk into pie shaped slices?
Q14. When computers use the cylinder method to store data on a hard disk pack, what three itemsmake up the address that tells the computer where on a specific disk to store the data?
Q15. What is the most common type of hard disk failure?
Q16. Hard disks should be stored in an environment that stays within what relative humidity andtemperature range?
Q17. What is the most common method for erasing a hard disk?
Q18. What are the three most popular methods for encoding digital data onto magnetic disks?
Q19. Older, single-sided, single-density floppy disk drives would probably use what method forencoding digital data onto the floppy disk?
Q20. What method for encoding digital data enables you to store more data in less space by limitingthe distance between pulses on a hard disk?
Q21. What are the four most important parts of a floppy disk drive transport?
Q22. The drive motor of a 3-1/2", 1.44-MB floppy disk drive spins the disk at what RPM?
Q23. The head arm assembly of a floppy disk drive transport has how many read heads and how manywrite heads?
Q24. What part of a floppy disk drive transport uses a dc stepper motor to position the magnetic headsover the recording surface of a floppy disk?
Q25. What part of a floppy disk drive transport contains the circuitry which controls theelectromechanical parts of the transport?
Q26. Hard disk drive transports contain the electromechanical parts that perform what threefunctions?
Q27. In the actuator arm assembly of a hard disk drive transport, what device can position themagnetic heads to the correct track of a hard disk more accurately than a dc stepper motor?
Q28. Why do floppy disk drives require more preventive maintenance than hard disk drives?
Q29. A kit for cleaning floppy disk drives contains what two items?
Q30. Approximately how often should you clean a floppy disk drive that gets heavy use?
Q31. Cartridge hard disk drives with 14" disk packs may require what additional types of preventivemaintenance?
Q32. The control electronics component of a floppy or hard disk drive performs what three mainfunctions?
Q33. The write/read electronics of a disk drive performs what three functions?
Q34. The interface electronics of a disk drive performs what three functions?
Q35. What type of interface electronics is used in many naval electronic warfare systems?
Q36. What type of disk drive interface has most of the electronics on a controller card mounted in thehost computer?
Q37. The SCSI is a high level disk drive interface. What does this mean?
Q38. What type of hard disk drive interface has all of the controller card electronics included in the disk drive itself?
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