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 : Which performance parameter is the minimum amount of optical power required to achieve a specific bit-error rate (BER) in digital systems or a given signal-to-noise ratio (SNR) in analog systems?
Last Answer : Receiver sensitivity.
Description : The multi-track tape recorder in your computer system has a fixed skew error. What does this mean and what is the probable cause?
Last Answer : Skew means there are time differences between the individual tracks of a multi-track recorder’s magnetic head. It happens when the tape isn’t properly aligned with the head. Fixed skew happens when the tape passes over an improperly aligned magnetic head.
Description : What are signal dropouts, and what are two tape defects that can cause signal dropouts?
Last Answer : Dropouts are temporary, sharp drops (50% or more) in signal strength. They’re caused by contaminates that lift the tape away from the magnetic
Description : Why does adding dc vice ac bias voltage to the input signal result in a poor signal-to-noise ratio (SNR)?
Last Answer : With dc bias, the SNR is poor because only a small portion of the magnetism curve is straight enough to use, thus the output signal is weak compared with the natural tape hiss.
Description : What effect does noise have on the fiber optic signal?
Last Answer : Noise obscures or reduces the quality of the signal.
Description : Which of the following refers to theterms "residual error rate"? A. the number of biterrors per twenty four hours of continuous operation onanasynchronous line B. The probability that one or moreerrors ... tonoise ratio dividedby the ratio of energy perbit to noise per hertz E. None of the above
Last Answer : The probability that one or moreerrors will be undetected whenan error detection scheme is used
Description : An error signal is the difference between what two quantities fed to the CT (error detector)?
Last Answer : Input signal and feedback.
Description : What condition produces the 10-kHz error signal generated by the metering bridge in the HP- 431C power meter?
Last Answer : An unbalance in the metering bridge.
Description : What causes flutter in a tape recorder’s output?
Last Answer : Non-uniform tape motion caused by variations in tape speed.
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 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 are four main causes of tape failure?
Last Answer : Normal wear, accidental damage, environmental damage, and winding errors.
Description : Which causes a quantization noise in PCM system? A. Serial transmission errors B. The approximation of the quantized signal C. The synchronization between encoder and decoder D. Binary coding techniques
Last Answer : B. The approximation of the quantized signal
Last Answer : The approximation of the quantized signal
Description : What causes image interference? A. Low gain B. High IF C. Poor front-end selectivity D. Low signal-to-noise ratio
Last Answer : C. Poor front-end selectivity
Description : The random and unpredictable electric signal from natural causes, both internal and external to the system is know as ________. A. Distortion B. Noise C. Attenuation D. Interference
Last Answer : B. Noise
Description : What signal causes FF2 to toggle?
Last Answer : Q output of FF 1 going LOW.
Description : what causes the initial and final pulses on the receiver output signal?
Last Answer : Leakage from the duplexer.
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 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 amount of flat tape or round cord is required to single lace a group of conductors?
Last Answer : Two and one-half times the length of the longest conductor in the group.
Description : Why is flat tape preferred instead of round cord when wire bundles are laced?
Last Answer : Round cord has a tendency to cut into the wire insulation.
Description : Why is friction tape used in splicing?
Last Answer : As a protective covering over the rubber tape.
Description : What equipment should you use to de-magnetize a magnetic tape transport?
Last Answer : A hand-held degausser.
Description : When cleaning the parts of a tape transport, why should you switch lint-free cloths and swabs often?
Last Answer : You may transfer dirt or oxide particles from one part of the tape transport to another
Description : Sometimes it's necessary, but why should you avoid using cotton swabs when cleaning a magnetic tape transport?
Last Answer : Cotton swabs are not lint free.
Description : How do dual-motor dual capstan drives maintain a constant tape tension while operating in either a forward or reverse direction?
Last Answer : Each capstan is driven by its own motor. It maintains tape tension by slowing down one of the motors. When the tape motion is reversed, the opposite motor is slowed down.
Description : . How do tape transports with differential velocity capstans maintain a constant tape tension in the area around the magnetic heads?
Last Answer : The supply capstan is slightly larger than the take-up capstan. This causes the take-up capstan to pull the tape slightly faster than the supply capstan feeds the tape.
Description : How do closed-loop capstan drive tape transports overcome the disadvantages of the open-loop drive design?
Last Answer : Closed loop capstan drive transports use more than one capstan to clamp the tape in the area around the magnetic head.
Description : There are two types of tape transport configurations, open loop capstan drive and closed-loop capstan drive. What are two major disadvantages of open-loop capstan drive tape transports?
Last Answer : a. Only operates in one direction. b. The tape tension and head-to-tape contact can vary.
Description : How do the tape guides on a tape reeling system protect the tape from damage during operation?
Last Answer : They keep the tape straight with respect to both the supply and take-up reels and the magnetic heads.
Description : What are the two basic types of tape buffering reeling systems?
Last Answer : a. Spring-tension buffering systems. b. Vacuum-column buffering systems.
Description : What are the three most commonly used tape reeling systems?
Last Answer : a. Take-up control. b. Two-motor reeling. c. Tape buffering.
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 : How do worn or sticking tape transport guides cause dynamic skew on a multi-track recorder?
Last Answer : The tape drifts past the multi-track head at an angle.
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 : Why is it important to minimize TBE jitter in magnetic tape recordings where precise timing relationships exist between two or more signals?
Last Answer : The jitter could cause noise and a loss of accuracy.
Description : How could you check the phase response of a tape recorder?
Last Answer : Record and reproduce a square wave and see if the output on an oscilloscope is symmetrical.
Description : How should a tape recorder with good phase response reproduce a complex waveform, such as a square wave?
Last Answer : With no distortion
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 : The frequency-response specification of your tape recorder reads within +/ - 3 dB from 150 Hz to 150 kHz at 60 ips. What does this mean?
Last Answer : The recorder can record all frequencies between 150 Hz and 150 kHz at 60 ips without varying the output amplitude more than 3 dB.
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 : The head driver circuit of a tape recorder’s FM record electronics (figure 5-4) performs what function?
Last Answer : It amplifies the frequency-modulated output from the record oscillator and sends it to the record head.
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.