3D152 Volume 1 UREs

"The modulating signal is represented as a band of frequencies (sine waves of different frequencies) extending from some lower frequency, fL, to some upper or highest frequency, fH. Notice that the output signal includes two bands of frequencies: one at frequencies above the carrier, fc, and one below the carrier. These we call the upper sideband and lower sideband, respectively. The upper sideband (USB) has the same shape and orientation as the band of modulating signal frequencies. The lower sideband (LSB), however, is the mirror image of the original modulating signal." Page 1-8

"Timing for digital devices fall into three categories: synchronous, asynchronous, and isochronous. These terms characterize the methods used to synchronize the send and receive devices." Page 2-4

"The only basic waveform in nature is a pure sine wave; any other waveform is a “composite” or “resultant” wave." Page 1-9

"The definition of analog modulation is the conversion of an analog signal (the information) into another analog signal (the carrier). The type of modulation technique depends on the feature of the carrier signal that is used to represent the information." Page 1-2

"The transmission line presents a delay in each section, and the amount of delay is dependent upon the
frequency of the information signal. Thus, a delay, also known as latency or lag, is introduced in the application of voltage from one section to the next" Page 3-6

"Disconnect all sources of voltage from the circuit before you connect an ohmmeter; if you connect it into a “hot” circuit, the meter may burn out." Page 3-12

"The transmitting multiplexer will put a bit or a byte from each of the incoming lines into a specifically allocated time slot" page 1-36

"if 100-percent modulation is exceeded and/or there is
distortion in the modulating signal, additional sidebands are generated because of the harmonic
content of the distorted modulating signal. These additional sidebands, known as splatter, cause
unwanted bandwidth and distortion in the transmitted AM signal." Page 1-10

"DPSK encodes different digital values as changes in signal phase. DPSK is easier to implement and is more robust than PSK because DPSK looks for differences, rather than for specific values. This form of modulation can be found in local area network technologies." Page 1-3

"When a signal transition occurs, the signal level moves to one of the discrete signal levels, but after a predetermined time (normally 50 percent of a bit), it returns to zero voltage (RZ).Figure 2–5 shows the three most common signal formats in the DII." Page 2-8

"The voltage or 48-volt battery is not activated until the telephone handset is lifted, off-hook." Page 2-13

"When you push the 50Ω button in, that action selects the 50Ω impedance. Push in the 75Ω button when you require the 75Ω impedance. With both buttons pushed in, the time domain reflectometer receives 125Ω impedance. When both buttons are out, it receives 95Ω impedance." Page 3-13

"T1 uses the TDM process (fig. 1–38). These inputs can be a combination of digital, video, and audio signals." Page 1-38

"In digital signals, we call each condition, state, or pulse a binary digit. We shorten this term to “bit.”" Page 2-1

"This process is shown in figure 1–5. Here, we use a filter that passes only the signal components in
the frequency range between fc – fH and fc – fL. Thus, the output of the filter contains only the lower
sideband. In particular, if we modulate a 27-MHz carrier frequency (in the Citizen’s Band frequency
range) with a voice signal band of 300 to 3400 Hz, the single-sideband suppressed carrier (SSBSC)
output is a band of frequencies between 26.9966 and 26.9997 MHz." Page 1-8

"At the distant end, the receiver receives the test pattern. The received pattern is compared with an identical pattern generated by the receiving BERT set. Therefore, a BERT can measure all disrupting influences that may cause errors. The errors, if any, are counted and displayed. The test set determines the bit error rate (BER) by comparing the bits received in error with the total number of bits received." Page 3-25

According to Air Force Doctrine Document (AFDD) 2–5.1, Electronic Warfare Operations, dated 5 November 2002, electronic attack is “the component of EW involving the use of electromagnetic, directed energy, or anti-radiation weapons to attack personnel, facilities or equipment with the intent of degrading, neutralizing or destroying enemy combat capability.” Page 3-9

"The test set consists of a data code generator (transmitter) section and a code detector (receiver)
section." Page 3-25

"The most common WDM system uses two wavelengths, although four or more-wavelength systems are available." Page 1-40

"The ESF frame is based on the D4 frame. The difference between ESF and D4 framing is that the ESF superframe consists of 24 frames to create a 24-bit framing sequence." Page 2-10

"Any actions that we take to protect our people, facilities, and equipment from any EA action that can degrade or destroy our capabilities, fall under the heading of EP." Page 3-9

"We can express the 6-to-1 improvement of SSBSC over DSBSC
as 8 decibels (dB) of improvement." Page 1-9

"When we express the term “bit” with regard to time, we have bits per second (b/s). This simply means that we can move a certain number of symbols, states, or conditions in 1 second. This method is commonly used in data systems to express signaling speed for equipment." Page 2-2

"The loop-start or metallic loop signaling method uses a continuous application of direct current voltage." Page 2-13

"The part of the scattered energy that travels back toward the optical source is called the “backscatter,” and it’s the basis for optical time domain reflectometer" Page 3-20

"The definition of digital modulation is the conversion of an analog signal (the information) into a digital signal (the carrier)." Page 1-3

"The number of steps needed is equal to 2n, where (n) is the number of code bits needed for the largest character. Thus, the 16-step system requires 4 bits per character (24=16) and a 128-step system requires 7 bits per character (27=128) to describe the quantized analog samples." Page 1-31

There are two major types of frame structures:
1. Low speed frame – used for rates below 384.2 kbps and is composed of a number of 8 bit slots with each slot holding one character
2. Consultative Committee for International Telephony and Telegraphy (CCITT) frame –used for data rates above 384.2 kilobytes per second (kb/s) and uses subframes (P1 and P2) to maintain sync during longer data frames.

Page 1-37

"Bipolar violations can occur on an AMI coded signal due to noise hits, crosstalk, and bad cable connections. Each successive logic 1 (mark pulse) is supposed to be the opposite polarity from the preceding logic 1 as the AMI definition above explains. A noise hit on the circuit can either cause a previous logic 0 (space pulse) to be converted to a logic 1 (addition) or cause a previous logic 1 to be converted to a logic 0 (deletion). This results in two successive logic one pulses of the same polarity, which is a violation of AMI coding rules. The total number of BPVs that have occurred during the test is displayed on the front panel of the test set." Page 3-27

"NRZ-M (mark). The information is contained in the transition, and there’s a transition from one state to the other only when a mark bit is sent." page 2-8

"electronic attack is “the component of EW involving the use of electromagnetic, directed energy, or anti-radiation weapons to attack personnel, facilities or equipment with the intent of degrading, neutralizing or destroying enemy combat capability.” This can be done by jamming a portion of the frequency spectrum, using anti-radiation missiles, noise jamming, or directed energy weapons." Page 3-9

"using an optical device, it sends light through to create the virtual channels using different wavelengths or lambdas then it multiplexes them together for transmission." Page 1-39

"In CAS signaling, the seventh bit in frames 6 and 12 are “robbed” to convey signaling information. This is known as bit robbing. The pattern represented robbed bit is based on the type of signaling, such as loop-start, or E&M, and the signal being conveyed." Page 2-13

"One distinct advantage of BPSK is its insensitivity to level variations." Page 1-18

"B8ZS intentionally inserts bipolar violations (BPV) into a data signal to break up long strings of zeros." Page 2-9

"Some models may have three input terminal jacks. The first (voltage) terminal jack is color-coded black and serves as the common terminal for all measurements and is always used." Page 3-10

"If the reading is unreadable due to fluctuations, the display hold mode freezes the display so that the reading can be obtained." Page 3-11

"Twenty-four miniature ON/OFF switches allow all interface conductors (except frame ground on pin 1) to be individually interrupted for isolated testing and observation." Page 3-29

"The RF bandwidth for a quadriphase signal is half that required by a bi-phase signal, given the same data rate. Alternatively, twice as much data might be transmitted in the same bandwidth with a quadriphase signal as with a bi-phase signal." Page 1-19

"The principle of operation for the time domain reflectometer is similar to that of radar. We apply a pulse from the time domain reflectometer to a cable under test. Any impedance changes in the cable causes a portion of that voltage or energy to be reflected back to the cable input." Page 3-12

"Tone dialing uses a two-frequency combination that is associated with 12 push button keys. Each row and column of keys is associated with a predefined frequency." Page 2-12

1. Associated mode – The messages relating to signaling between two points are conveyed directly interconnecting these signaling points.
2. Nonassociated mode – The messages relating to signaling are conveyed over two or more links passing through one or more signaling points that are not the origin and the destination of the messages.
3. Quasi-associated mode – This is a subcase of the nonassociated mode. The path the messages take through the network is predetermined and fixed.

Page 2-14

"ES includes devices such as radar warning receivers and intelligence platforms." Page 3-9

"Synchronous operation requires no synchronizing pulses in the signal stream, and all bits are the same length in time." Page 2-4

"A dial tone is a frequency pair used to convey informational signaling. For example, the generation of a continuous 350- and 440-Hz frequency pair by the switch equipment." Page 2-12

"The local switch equipment generates a busy signal to the sender when the receiver’s line is in use. For example, a signal cycled on and off for 0.5 second and contains the generation of a 480- and 620-Hz frequency pair." Page 2-12

"The amount of phase shift is proportional to the amplitude of the modulating signal (that is, if a 10-volt signal causes a phase shift of 20 degrees, then a 20-volt signal causes a phase shift of 40 degrees)." Page 1-16

"The two principal weighting characteristics in current use are (1) CCITT (Consultative Committee for International Telephony and Telegraphy) psophometric, a noise weighting used in Europe with a noise (or level) meter called a psophometer, weighting and (2) C-message weighting." Page 3-2

"The capability for regeneration of quantized pulses can be further enhanced by coding the pulses to make them of constant duration and amplitude before transmission" Page 1-32

"Amount of deviation in FM is proportional to the amount (amplitude) of the modulating signal." Page 1-13