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138. In a frequency synthesizer, smallest amount which output frequency can be changed? Ans. resolution * 139. Internal capacitance, causes feedback produces same effect on…Ans. Miller effect * 140. Small length of wire found in some RF equipment, connected only at one end and use as a capacitance to ground. Ans. gimmick * 141. Movement of signal from one frequency to another using mixer-oscillator combination. Ans. frequency translation * 142. Feature of modulating tone, FM deviation is proportional Ans. amplitude * 143. Modulating 2 waves of the same frequency, but with _____ phase difference is equivalent to modulating both amplitude and phase of the same carrier. Ans. 90 degrees * 144. Frequency of unmodulated carrier of an FM. Ans. rest frequency * 145. What determines stations that will be selected by a tuner? Ans. resonant frequency of tuner * 146. Periodic waveforms consist of add harmonics. Ans. square wave * 147. Major problem with VHF oscillator. Ans. poor frequency stability * 148. What happens to a spectrum of repetitive pulse as the pulse width decrease? Ans. more harmonics of the same phase * 149. Keyed AGC is AGC that Ans. is used in TV receivers *
150. Main disadvantage of single-tube transmitter. 151. What is reduced by rounding off squarewave emission. 153. Multiplexing, oldest and simplest. Ans. space division multiplexing * 154. Device display signal state of many lines simultaneously. Ans. logic analyzer * 155. Most common IF carrier frequency. Ans. 70 MHz * 156. Citizen Band (CB) Radio Service is a two-way voice communication device, it uses frequency range from ______ MHz. Ans. 26.965 to 27.405 * 157. What determines the rate of frequency swing for an FM broadcast transmitter? Ans. modulation frequency * 158. In PLL demodulating an FM signal. Ans. VCOout = FMin * 159. In PLL frequency modulator, fmAns. error signal * 160. Find the modulation index if a 10V carrier is amplitude-modulated by three different frequencies with amplitudes of 1V, 2V, and 3V, respectively. 161. Calculate the modulation index for a waveform with a maximum voltage of 150V and minimum voltage of 70V. 162. An AM broadcast transmitter has a carrier power output of 50 kW. What is the total power would be produced with 80% modulation? Ans. 66 kW 163. An AM broadcast transmitter has a carrier power output of 50 kW. What is the power in one sideband with 80% modulation?