Description : The head driver circuit in a tape recorder’s direct record electronics component (figure 5-1) performs what function?
Last Answer : It takes the signal from the summing network, amplifies it, and sends it to the record head for recording.
Description : The equalization and phase correction circuit in a tape recorder’s direct reproduce electronics (figure 5-2) performs what function?
Last Answer : It generates an equalization signal which corrects any frequency response problems in the input signal from the pre-amplifier circuit.
Description : What two types of record and reproduce electronics are used by magnetic tape recorders?
Last Answer : . a. Direct record (AM). b. Frequency modulation (FM).
Description : Two tape recorders have signal-to-noise ratios (SNRs) of 25-dB RMS and 35-dB RMS respectively. Which of the SNRs can record and reproduce the widest range of input signals and why?
Last Answer : 35-dB RMS because the highest SNR can always record and reproduce the widest range of input signals.
Description : What method for erasing magnetic tape is much more effective and reliable than using a recorder’s erase head?
Last Answer : Using a magnetic tape degausser
Description : What are two disadvantages of using a recorder’s erase head to erase data recorded on a magnetic tape?
Last Answer : Using an erase head is slow, and it may not completely erase the tape.
Description : How do FM record electronics differ from AM (direct record) electronics?
Last Answer : Instead of recording the signal just as it appears at the recorder’s input, FM record electronics records a frequency-modulated carrier signal from a record oscillator (figure 5-4) onto the magnetic tape
Description : A recorder's erase head is always placed in what sequence on the record/reproduce track?
Last Answer : . First, before the record and reproduce heads.
Description : What type of reeling system best controls a tape recorder's tape tension during starts and stops?
Last Answer : A tape buffering reeling system
Description : What are the four basic parts of a magnetic tape recorder's tape transport system?
Last Answer : a. Tape reeling system. b. Tape speed control system. c. Electronic subsystem. d. Basic enclosure.
Description : What causes flutter in a tape recorder’s output?
Last Answer : Non-uniform tape motion caused by variations in tape speed.
Description : What number harmonic is the primary harmonic distortion in magnetic tape recorders?
Last Answer : Third-order harmonic.
Description : List four factors that can degrade the frequency response of magnetic tape recorders.
Last Answer : a. A too-high or too-low bias signal level setting for the record head. b. An improper reproduce head gap. c. An improper tape transport speed. d. Poor tape-to-head contact.
Description : Technical manuals for tape recorders can state the SNR in what three different ways?
Last Answer : a. Root-mean-square (RMS) signal-to-RMS noise. b. Peak-to-peak signal-to-RMS noise. c. Peak signal-to-RMS noise.
Description : You plan to measure your tape recorder’s SNR. What test equipment will you need?
Last Answer : A VTVM and a signal generator.
Description : Magnetic tape recorders can have up to three different heads installed. What are the three functions performed by a recorder's heads?
Last Answer : Record, reproduce, and erase.
Description : After using a tape that was stored in an area where temperatures exceeded 130º F you notice pieces of oxide sticking to the recorder's tape-transport mechanism, to its magnetic heads, and onto the tape. What is the probable cause of these symptoms?
Last Answer : Oxide shedding. At temperatures above 130º F, oxide coating becomes soft and sheds.
Description : Digital magnetic tape recorders used to store and retrieve digital data fall into what three categories?
Last Answer : a. Computer-compatible digital tape recorders. b. Telemetry digital tape recorders. c. Instrumentation digital tape recorders
Description : Which digital data encoding method helps overcome a tape recorder’s low-frequency response problems by recording two logic levels for each incoming data bit?
Last Answer : Bi-phase level encoding.
Description : Which single phase ac motor will you select for record players and tape recorders? a) Hysteresis motor b) Shaded pole motor c) Reluctance motor d) Two value capacitor motor
Last Answer : Which single phase ac motor will you select for record players and tape recorders? Hysteresis motor
Description : The control electronics component of a floppy or hard disk drive performs what three main functions?
Last Answer : a. Spins the disk at the correct speed. b. Moves the heads across the recording surface. c. Tells the write/read heads when to write data and when to read it.
Description : Why are record heads always placed before reproduce heads on recorders?
Last Answer : Allow you to monitor the signals you're recording.
Description : What two specifications determine the maximum frequency that a recorder's record and reproduce heads will be able to transfer?
Last Answer : a. Size of the headgap. b. Speed of the magnetic tape.
Description : What is the major difference between direct reproduce electronics and FM reproduce electronics?
Last Answer : FM record electronics must use a limiter and demodulator circuit (figure 5-5) to demodulate the signal intelligence from the carrier frequency.
Description : What type of magnetic tape is used to record computer programs and data, and what are the additional thickness and quality standards for this type of tape?
Last Answer : digital magnetic tape is for computer programs and data. Its base material is about 50% thicker. The tape’s surface must not have blemishes or coating flaws because losing even one digital data bit could ruin the recorded computer program or data.
Description : Which of the two types of magnetic tape is used to record audio and instrumentation type signals in the VLF to 2.5MHz frequency range?
Last Answer : Analog magnetic tape.
Description : What category of digital tape recorder is used to record special signals with a bandwidth of less than 500 kHz?
Last Answer : Instrumentation digital tape recorders.
Description : What format of digital tape recording is normally used to record instrumentation or telemetry data?
Last Answer : Serial digital magnetic tape recording.
Description : A tape pack has gaps in the tape winding as shown in figure 2-5. What causes this condition?
Last Answer : Tape is loosely wound on reel.
Description : A recorder’s harmonic-distortion specification reads 2% third harmonic of a 100-kHz signal at 60 ips. What does this mean?
Last Answer : The recorder has 2% third-harmonic distortion of a 100-kHz signal at 60 ips.
Description : How often should you demagnetize a recorder's magnetic heads?
Last Answer : Every 8 to 25 hours depending on the manufacturer's recommendations.
Description : What type of equipment should you use to demagnetize your recorder's magnetic heads?
Last Answer : A hand-held degausser like the manual degaussers used for degaussing magnetic tape.
Description : How should you clean your recorder's magnetic heads?
Last Answer : With a cotton-tipped applicator soaked in either isopropyl alcohol or a head cleaner recommended by the recorder's manufacturer.
Description : A tape pack is buckled and deformed as shown in figure 2- 4. What are three possible causes for this condition?
Last Answer : a. Reel has a distorted hub, b. tape wound over small particle deposited on hub, and c. tape wound on reel with tension increasing toward end of winding.
Description : You notice steps in the tape pack such as those in figure 2-3. What causes this and how does it damage the magnetic tape?
Last Answer : Pack slip. It's caused by loosely wound tape on a reel that is exposed to excessive vibration or heat. The vibration or heat causes the tape to shift, causing steps in the tape pack. The uneven tape will then rub against the reel's sides and the recorder's tape guides.
Description : . After rewinding a tape onto its supply reel, you examine the tape pack and notice pile-ups of tape resembling the example in figure 2-2. What causes this condition?
Last Answer : The tape is stopped too quickly when winding or rewinding.
Description : What is the function of an fm detector?
Last Answer : Converting frequency variations of received fm signals to amplitude variations
Description : The skew specification of your multi-tracked tape recorder reads " +/ - 0.20 microseconds between adjacent tracks on the same head stack at 120 ips." What does this mean?
Last Answer : One of the tracks on a magnetic head could lead or lag the track next to it by as much as 0.20 microseconds at 120 ips.
Description : What two preventive maintenance actions must you do regularly to increase magnetic head life and to ensure good tape recording and playback?
Last Answer : a. Keep the heads clean. b. Keep the heads demagnetized.
Description : How does relative humidity over 95% cause excessive tape and head wear?
Last Answer : High humidity causes increased friction as the tape passes over the heads.
Description : In the subtract mode, a 1 at C0 performs what portion of the R’s complemen
Last Answer : Add 1 portion.
Description : Multimode optical fibers can have a step-index or graded index refractive index profile. Which fiber, multimode step-index or multimode graded-index fiber, usually performs better?
Last Answer : Multimode graded-index fiber
Description : What is a central set of programs called that manages the execution of other programs and performs common functions like read, write, and print?
Last Answer : Operating system.
Description : In a circuit such as that shown in figure 3-15, if R1 has a value of 100 ohms and R2 has a value of 1 kilohm and the input signal is at a value of + 5 millivolts, what is the value of the output signal?
Last Answer : 50 millivolts.
Description : What type of objects are most easily detected by an fm system?
Last Answer : Stationary.
Description : What factor determines the difference between the transmitted frequency and the received frequency in an fm transmitter?
Last Answer : Travel time.
Description : What happens to an fm signal as you increase the frequency of the modulating signal?
Last Answer : Both the bandwidth and the number of significant sidebands increase.
Description : What is the major disadvantage of an fm signal as compared to an AM signal?
Last Answer : Wide bandpass.
Description : In an fm transmitter, when does an oscillator generate only a steady frequency?
Last Answer : When no modulation is present.
Description : Why can phase-modulated signals be detected by fm detectors?
Last Answer : Because of the incidental frequency shift that is caused while phase-shifting a carrier wave that is similar to fm modulation.