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 : 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 two types of record and reproduce electronics are used by magnetic tape recorders?
Last Answer : . a. Direct record (AM). b. Frequency modulation (FM).
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 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 : 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 : 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 : What are the three functions of the magnetic heads on a magnetic recording device?
Last Answer : a. Record the signal onto the recording medium. b. Reproduce the signal from the recording medium. c. Erase the signal from the recording medium.
Description : LEDs operating at 850 nm provide sufficient optical power for short-distance, low-bandwidth multimode systems. List three conditions that prevent the use of LEDs in longer distance, higher bandwidth multimode systems.
Last Answer : Multimode fiber dispersion, the relatively high fiber attenuation, and the LED's relatively low optical output power.
Description : Modal dispersion affects the bandwidth of multimode systems. It is essential to adjust what three fiber properties to maximize system bandwidth?
Last Answer : Core diameter, NA, and index profile properties.
Description : The vertical-deflection plates are used to reproduce what function?
Last Answer : Amplitude.
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 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 : 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 does the simplest diode detector use to reproduce the modulating frequency?
Last Answer : The modulation envelope.
Description : The field arrangements in waveguides are divided into what two categories to describe the various modes of operation?
Last Answer : Transverse electric (TE) and transverse magnetic (TM).
Description : What are the two main categories of maintenance?
Last Answer : Preventive and corrective maintenance.
Description : Air-search radar is divided into what two basic categories?
Last Answer : 2D and 3D.
Description : Fiber splicing is divided into two broad categories that describe the techniques used for fiber splicing. What are they?
Last Answer : Mechanical and fusion splicing.
Description : How many categories of nonmetallic protective coverings are there?
Last Answer : Three
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 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 : What are four sources that can cause magnetic heads to become magnetized?
Last Answer : a. During ac power losses. b. During testing. c. Because of stray magnetic fields. d. From normal use.
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 : 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 : In the actuator arm assembly of a hard disk drive transport, what device can position the magnetic heads to the correct track of a hard disk more accurately than a dc stepper motor?
Last Answer : Voice coil servo.
Description : What part of a floppy disk drive transport uses a dc stepper motor to position the magnetic heads over the recording surface of a floppy disk?
Last Answer : Actuator arm assembly.
Description : The head arm assembly of a floppy disk drive transport has how many read heads and how many write heads?
Last Answer : Two read heads and two write heads.
Description : What determines the frequency, bandwidth, and power handling capability of a waveguide probe?
Last Answer : Size and shape
Description : What is the bandwidth of an amplifier?
Last Answer : The difference between the upper and lower frequency limits of an amplifier.
Description : If the unity-gain point of the operational amplifier used in question 24 is 500 kilohertz, what is the bandwidth of the circuit?
Last Answer : 50 kilohertz (Gain = 10; Gain-Bandwidth Product = 500,000) 500,000(Hz)
Description : What is the advantage of designing a limited bandwidth into a servo amplifier?
Last Answer : Unwanted noise-generated frequencies are rejected
Description : Receiver bandwidth is defined as those frequencies spread between what two points of the receiver response curve?
Last Answer : Half-power points.
Description : While coupled power and bending loss favor a high D, which Dvalue, smaller or larger, improves fiber bandwidth?
Last Answer : Smaller.
Description : Light travels faster in a material with a lower refractive index. Therefore, light rays that travel a longer distance in a lower refractive index travel at a greater average velocity. What effect does this have on multimode graded-index fiber modal dispersion and bandwidth?
Last Answer : Decreases the time difference between light rays, which reduces modal dispersion and increases fiber bandwidth.
Description : Which preamplifier design (high-impedance or transimpedance) provides improvements in bandwidth and greater dynamic range with some degradation in sensitivity from an increase in noise?
Last Answer : Transimpedance.
Description : In a multicavity klystron, tuning all the cavities to the same frequency has what effect on the bandwidth of the tube?
Last Answer : The bandwidth decreases.
Description : What two values may be used to determine the bandwidth of an fm wave?
Last Answer : The number of significant sidebands and the modulating frequency.
Description : What determines the bandwidth of an AM transmission?
Last Answer : The highest modulating frequency.
Description : While measuring frequency response, as the signal generator approaches the lowest and highest frequency the recorder can effectively record, the VTVM reading drops to less than - 3 dB. What does this indicate?
Last Answer : The upper and lower limits of the frequency response specification for that tape recorder.
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 : 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 : 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 : 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 precedes each record on a disk?
Last Answer : A disk address
Description : What format of digital tape recording is normally used to record instrumentation or telemetry data?
Last Answer : Serial digital magnetic tape recording.