CHAPTER 7 ANGLE MODULATION TRANSMISSION
1) Two forms of angle modulation. FM and PM
2) Angle modulation was first introduced in the year ________ as an alternative to amplitude modulation. 1931
3) He developed the first successful FM radio system in 1936, and in July 1939, the first regularly scheduled broad-casting of FM signals began in Alphine, New Jersey. Also developed the superheterodyne receiver. Major E. H. Armstrong
4) A modulation that results whenever the phase angle 
of a sinusoidal wave is varied with respect to time. Angle Modulation
of a sinusoidal wave is varied with respect to time. Angle Modulation5) Varying the frequency of a constant-amplitude carrier directly proportional to the amplitude of the
modulating signal at a rate equal to the frequency of the modulating signal. Direct Frequency Modulation ( FM )
6) Varying the phase of a constant-amplitude carrier directly proportional to the amplitude of the modulating signal at a rate equal to the frequency of the modulating signal. Direct Phase Modulation ( PM )
7) The relative angular displacement (shift) of the carrier phase in radians in respect to the reference phase. Phase Deviation 
8) The relative displacement of the carrier frequency in hertz in respect to its unmodulated value. Frequency Deviation
9) The original unmodulated carrier frequency in the resultant angle-modulated waveform. Carrier Rests Frequency
10) The instantaneous change in the phase of the carrier at a given instant of time and indicates how much the phase of the carrier is changing with respect to its reference phase. Instantaneous Phase Deviation
11) The precise phase of the carrier at a given instant of time. Instantaneous Phase
12) The instantaneous change in frequency of the carrier nd is defined as the first time derivative of the instantaneous phase deviation. Instantaneous Frequency Deviation
13) The precise frequency of the carrier at a given instant of time and is defined as the first time derivative of the instantaneous phase. Instantaneous Frequency
14) Are the output–versus-input transfer functions for the modulators, which give the relationship between what output parameter changes in respect to specified changes in the input signal. Deviation Sensitivities
15) Is called the modulation index or sometimes index of modulation. Peak Phase Modulation
16) The change in frequency that occurs in the carrier when it is acted on by a modulating-signal frequency. Frequency Deviation
17) The peak-to-peak frequency deviation 
. Carrier Swing
. Carrier Swing 18) The ratio of the frequency deviation actually produced to the maximum frequency deviation allowed by law stated in percent form. Percent Modulation
19) A circuit in which the carrier is varied in such a way that its instantaneous phase is proportional to the modulating signal. Phase Modulator
20) A circuit which the carrier is varied in such a way that its instantaneous phase is proportional to the integral of the modulating signal. Frequency Modulator
21) ________ of the first kind for several values of modulation index provides the number of side frequency pairs and their corresponding magnitude. Bessel Function
22) A side frequency is not considered significant unless it has an amplitude equal to or greater than ____ of the unmodulated carrier amplitude. 1%
23) The modulation index is less than 1. Low-index Case
24) The modulation index is greater than 10. High-index Case
25) Modulation indices greater than 1 and less than 10. Medium Index
26) Low-index FM systems are sometimes called? Narrowband FM
27) A rule which is an approximation and gives transmission bandwidths that are slightly narrower than the bandwidths. It defines a bandwidth that includes approximately 98% of the total power in the modulated wave. Carson’s Rule
28) The worst-case modulation index and is equal to the maximum peak frequency deviation divided by the maximum modulating-signal frequency. Deviation Ratio ( DR )
29) The FCC has assigned the commercial FM broadcast service a _______ band of frequencies that extends from 88 MHz to 108 MHZ. 20 MHz
30) The 20–MHz band is divided into 100, ________ wide channels beginning at 88.1 MHz. 200 kHz
31) To provide high-quality, reliable music, the maximum frequency deviation allowed is _______ with a maximum modulating-signal frequency of _______. 75 kHz ; 15 kHz
32) The highest side frequencies from one channel are allowed to spill over into adjacent channels, producing an interference known as _______. Adjacent Channel Interference
33) A _______ wide guard band is usually on either side of each assigned channel. 200 kHz
34) The noise voltage at the output of an FM demodulator increases linearly with frequency. This is called ______. FM Noise Triangle
35) The high-frequency modulating signals are emphasized or boosted in amplitude in the transmitter prior to performing modulation. Pre-emphasis
36) The reciprocal of pre-emphasis that restores the original amplitude-versus-frequency characteristics to the information signals. De-emphasis
37) A circuit that provides a constant increase in the amplitude of the modulating signal with an increase in frequency. Pre-emphasis Network
38) When the frequency of the carrier is modulated by the information signal, _______ results. Direct FM ( Indirect PM )
39) When the phase of the carrier is modulated by the information signal, _______ results. Direct PM ( Indirect FM )
40) Angle modulation in which the frequency of the carrier is varied directly by the modulating signal. Direct FM
41) Three common methods for producing direct frequency modulation. Varactor Diode, FM Reactance, Linear IC Modulations
42) Direct frequency modulator used for low-index Applications, such as two-way mobile radio. Varactor Diode Direct FM Modulator
43) A direct FM modulator using a JFET as the active device. FM Reactance Modulator
44) A complete FM modulator on a single 8-pin DIP integrated circuit chip. MC1376
45) Can generate a direct FM output waveform that is relatively stable, accurate, and directly proportional to the input modulating signal. Linear IC VCO and Function Generators
46) Angle modulation in which the frequency of the carrier is deviated indirectly by the modulating signal. Direct PM
47) Two common methods for producing direct phase modulation. Varactor Diode and Transistor Direct PM Modulator
48) The process of up-converting the frequency of the modulated carrier after modulation has been performed. Frequency Up-Conversion
49) Two basic methods of performing frequency up-conversion. Heterodyning and Frequency Multiplication
50) An up-conversion method where a low-frequency modulated carrier can either be up- or down-converted to a different location in the frequency spectrum without changing its modulation properties. Heterodyne Method
51) An up-conversion method where the modulation properties of a carrier can be increased at the same time that the carrier frequency is up-converted. Multiplication Method
52) Transmitters that produce an output waveform in which the frequency deviation is directly proportional to the modulating signal. Direct FM Transmitters
53) A circuit that compares the frequency of he non crystal carrier oscillator to a crystal reference oscillator and then produces a correction voltage proportional to the difference between the frequencies. Automatic Frequency Control ( AFC )
54) A frequency-selective device whose output voltage is proportional to the difference between the input frequency and its resonant frequency. Frequency Discriminator
55) A voltage added to the modulating signal to automatically adjust the master oscillator’s center frequency to compensate for the low-frequency drift. dc Correction Voltage
56) A ________ preceded by a differentiator generates a PM waveform. FM Modulator
57) Transmitters that produce an output waveform in which phase deviation is directly proportional to the modulating signal. Indirect FM Transmitters
58) Probably the most significant advantage of angle modulation transmission over amplitude modulation transmission. Noise Immunity
59) Allows a receiver to differentiate between two signals received with the same frequency. Capture Effect
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