Mcq test.. communication.pdf

-----"‫ "بسم اهلل الرحمن الرحيم‬------- By..... " Hisham Mohamed Elruby ". "‫"الملف األول‬ ​. In FM, the carrier frequency deviates with changes in what 1 parameter(s) of the message signal? a. phase angle and amplitude b. frequency only c. amplitude only...

-----"‫ "بسم اهلل الرحمن الرحيم‬------- By..... " Hisham Mohamed Elruby ". "‫"الملف األول‬ ​. In FM, the carrier frequency deviates with changes in what 1 parameter(s) of the message signal? a. phase angle and amplitude b. frequency only c. amplitude only d. frequency and amplitude 2. In PM, the carrier frequency deviates with changes in what parameter(s) of the message signal? a. modulation index b. frequency only c. amplitude only d. frequency and amplitude. Why can a limiter circuit be used to cut off the peaks and valleys of an FM or PM signal? Edit with Acrobat a. The message signal is contained in the frequency and phase deviations of the carrier, not in the amplitude variations, b. The message signal causes only small changes in the amplitude of the carrier. c. FM or PM signals do not require much transmission power. d. All of the above. 4. A 4 kHz message signal causes an FM carrier signal to have a frequency deviation of +20 kHz. What is the MI? MI = fcd/fm a. 80 b. 5 c. 0.2 d. 24 5. An FM carrier signal with a Ml of 4 contains a 3 kHz message signal. Use the table to determine the number of significant sideband pairs, and then calculate the bandwidth of the FM carrier. Type here to search a. 12 kHz b. 6 kHz c. 42 kHz d. 21 kHz 1. What function does a discriminator or frequency detector perform? a. It converts FM frequency deviations into phase deviations. b. It limits the amplitude of an FM signal. c. It converts FM frequency deviations into the message signal. d. It removes the FM sum frequency from the recovered message signal. 2. What does the term quadrature mean? a. a frequency difference of 45 kHz b. a phase difference of 90° c. shifting the phase of a signal d. limiting the phase difference to 45° 3. What function does the quadrature detector first perform? a. It shifts the phase of the FM center frequency by 90°. b. It filters the FM signal. c. It converts phase deviations to frequency deviations. d. It converts phase deviations to the message signal. 4. What is the quadrature detector's phase detector? a. filter b. limiter c. balanced modulator d. LC network 5. What are the output signals of the quadrature detector's phase detector? a. signals equal to half and three times the FM center frequency b. the sum frequency of the inputs and the FM center frequency c. FM signals that are 900 out of phase d. the sum frequency of the inputs and a dc voltage that varies with the message signal 1. Frequency modulation (FM) and phase modulation (PM) are subcategories of what type of modulation? a. amplitude modulation b. SSB modulation c. angle modulation d. double sideband (DSB) modulation 2. When the message signal amplitude is zero, the FM carrier signal is at what frequency? a. maximum frequency b. minimum frequency c. deviation frequency d. center frequency 3. For an FM signal, what does the term frequency deviation mean?. a. the center frequency plus the modulation percentage. b. the change in frequency from the center frequency c. the modulation index times the center frequency d. the message signal frequency plus or minus the center frequency 4. For commercial broadcasts, the FCC has defined 100% modulation as a positive and negative frequency change of how many kHz around the center frequency? a. 150 kHz b. 75 kHz c. two times the center frequency d. 100 kHz 5. Changes in the message signal amplitude and frequency cause frequency deviations in what type of modulation? a. PM b. AM c. FM d. SSB 6. The number of significant sideband pairs in an FM signal is a function of what parameter? a. bandwidth b. percentage of modulation C.MI d. center frequency 7. What is the function of a discriminator? a. It restores high-frequency message signals to their proper relationship with the lower frequencies. b. It recovers the message signal from frequency deviations of the FM carrier signal. c. it provides the necessary amplification and volume control for the recovered message signal, d. It tunes the FM receiver to the desired frequency. 8. The phase shifter section of the quadrature detector shifts what FM signal frequency by 90°? a. upper sideband frequencies b. lower sideband frequencies c. center frequency d. All of the above. 9. The received FM signal has a center frequency of 95 MHz. What is the difference frequency output component of the quadrature detector's phase detector? a. 180 Mhz b. 95 Mhz c. a dc voltage d. 0 MHz 10.Why can random noise be reduced better in FM than in an AM? a. FM produces less noise than AM. b. FM signal amplitude variations do not contain the message signal, so the amplitude can be limited. c. FM signals are propagated via the ionosphere d. In FM, frequency and amplitude deviations contain the message signal. "‫"الملف الثاني‬ 1. Camer signals may have a frequency from 10 kHz to 1000 GHz. In the PROCEDURE section, you used a 1000 kHz carrier signal. What is the frequency range of message signals? a. 1 Hz to 10 Hz b. 30 Hz to 50 kHz c. 20 Hz to 20 kHz d. 100 kHz to 200 kHz 2. What is the process of combining a message signal with a carrier signal for communication over long distances? a amplification b filtering c demodulation d. modulation 5. In the PROCEDURE section, what function did the ENVELOPE DETECTOR perform? a. mixing b. amplification c. demodulation d. modulation 1. How do you adjust the frequency of the VCO-Hi oscillator signal? a by tuming the NEGATIVE SUPPLY knob on the base unit b. by inserting a two-post connector in the 1000 kHz terminals c. by tuming the POSITIVE SUPPLY knob on the base unit d by turning the potentiometer knob on the VCO-HI circuit block 2. How do you adjust the amplitude of the VCO-LO oscillator spor a. by tuming the NEGATIVE SUPPLY knob on the base unit b. by turning the potentiometer knob on the MODULATOR c. by tuming the POSITIVE SUPPLY knob on the base unit d. by turning the potentiometer knob on the VCO-LO circuit block 3. On the MODULATOR in the AM/SSB TRANSMITTER circuit block, how do you adjust the modulation of the carrier by the message signal? a. by turning the potentiometer knob on the MODULATOR b. by adjusting the frequency of the carrier signal c. by adjusting the frequency of the message signal d. by turning the NEGATIVE SUPPLY knob on the base unit 4. The VCO-LO, PHASE MODULATOR, QUADRATURE DETECTOR, and PHASE-LOCKED LOOP circuit blocks are associated with what type of radio signals? a. amplitude modulated (AM) signals b. single sideband (SSB) signals c. angle modulated (FM and PM) signals d. double sideband (DSB) signals 5. On the ANALOG COMMUNICATIONS circuit board, how do you connect the AM transmitter to the AM receiver? a A connection is not required because the signal is radialed by an antenna. b. Insert a two-post connector between R10 and the RF AMPLIFIER c Place switch S3 in the ON position d. Insert a two-post connector between FROM TRANSMITTER and Rå. 1. On the circuit board, what is the function of a balanced modulator? a. mixer b. amplitude modulator c. detector d. All of the above. 3. How is the carrier signal suppressed in the output of a balanced modulator? a. It is suppressed by the NEGATIVE SUPPLY voltage. b. It is suppressed by the POSITIVE SUPPLY voltage c. It is suppressed by the null potentiometer in the message signal input. d. It is suppressed by adjusting the VCO-LO potentiometer 4. To a balanced modulator, the camer signal is 1000 kHz and the message signal is 3 kHz. What are the sum and difference frequencies in the output? a. 997 kHz and 1003 kHz b. 994 kHz and 997 kHz c. 1003 kHz and 1006 kHz d. 994 kHz and 1006 kHz 5. When only the sum frequency is desired from a balanced modulator, what device removes the lower frequencies? a. a mixer b. a product detector c. a filter d. an automatic gain control circuit 1. A communication system requires a sender (transmitter), a transmission line or channel (frequency), and a receiver. What do you call a communication system that sends and receives information? a unidirectional b. amplitude modulated c. frequency modulated d. bidirectional what 2. What is the process of the low frequency message signal changing a characteristic of a high frequency carrier signal? a. mixing b. demodulation c. modulation d. detection 3. What do you call the frequency range of the sidebands around a carrier frequency? a. bandwidth b. message signal c. noise d. modulated frequency 4. What is the function of a product detector, quadrature detector, phase- locked loop, and envelope detector? a. modulation b. demodulation c. filtering d. mixing 5. What are the functions of the VCO-LO and VCO-HI circuit blocks? a. mixing and demodulation b. message signal generation c. oscillator signal generation d. phase modulation 6 What is the function of the RF POWER AMPLIFIER and the RF AMPLIFIER? a They increase the power level of the message signal to the speaker b. They increase the power level of the message and carrier signals to the modulator. c. They function as the automatic gain control d. They increase the power level of the transmitted and received signals, respectively. 7. The VCO-LO, PHASE MODULATOR, QUADRATURE DETECTOR, and PHASE-LOCKED LOOP circuit blocks possess what type of signals? a. Single Sideband (SSB) signals b. Double Sideband (DSB) signals c. Amplitude Modulated (AM) signals d. angle modulated signals 8. What is the function of a balanced modulator? a. modulation b. phase detection c. mixing d. All of the above. 9. A less than 100% modulated AM signal is output from a modulator that is not balanced. What significant output frequencies are present? a. the upper sideband, lower sideband, and carrier frequencies b. the message and carrier frequencies c. the upper sideband and lower sideband frequencies d. just the carrier 10. What device removes the Lower Sideband (LSB) from a Double Sideband (DSB) signal? a. limiter b. filter c. detector d. mixer 1. When the message signal frequency and amplitude change, what happens to the envelope of the AM signal? a. Only the amplitude of the AM signal envelope changes. b. Only the frequency of the AM signal envelope changes. c. The frequency and amplitude of the AM signal envelope change. d. The frequency and amplitude of the carrier signal change. 2. If a 2000 kHz carrier signal (f) is amplitude modulated by a 3 kHz message signal (fm), what frequencies are present in the frequency spectrum of the AM signal? a. 3 kHz, 6 kHz, and 2000 kHz b. 1997 kHz, 2000 kHz, and 2003 kHz c. 2000 kHz and 2003 kHz d. 1997 kHz and 2003 kHz 1. What is the function of the RF power amplifier? a. It amplifies the message signal to the AM modulator. b. It amplifies the carrier signal to the AM modulator. c. It provides the power amplification for the antenna to radiate the RF signals over long distances. d. It sets the frequency range for the antenna RF signal. 2. What is the purpose of an antenna matching network in an RF power amplifier? a It matches the RF power amplifier's low output impedance with with the low impedance of the antenna b. It matches the carrier and message signals. It matches the antenna impedance to the carrier signal frequency d. It sets a high enough output impedance for the RF power amplifier to provide sufficient power to the low impedance antenna. 3. If the current to an RF power amplifier is 25 mA and the input voltage is 5 Vrms, what is the amplifier input power? a. 125 mW b. 5mW c. 30 mW d. 1.25 mW 4. If the RF power amplifier input power is 2W and the output power to the antenna matching network is 5000W, what is the power gain? a 10,000 b. 2500 c. 5002 d. 1000 5. If the total AM signal power (Pr) to the antenna is 5000W and the antenna carrier power (Pc) is 3400W, what is the antenna sideband power (Ps)? a. 8400W b. 1600W c. 800W d. 3200W 1. If the message signal to an amplitude modulator is a voice signal, the envelope of the AM signal will have what type of waveform? a. sine waveform b square waveform c triangular waveform d. an irregular waveform 2. If a 3 kiz message signal modulates an 800 kHz camer signal, what frequencies are contained in the AM radio signal? a. 797 kHz, 800 kHz, and 803 kHz b. 3 kHz and 800 kHz c. 800 kHz and 803 kHz d. 797 kHz and 803 kHz 6. If the antenna matching network of an RF power amplifier is adjusted to an impedance of 6500, and if the antenna impedance is 502, what is the output impedance of the RF amplifier? a. 7000 b. 6000 c. 6500 B. 500 7. The input power to an RF power amplifier with a gain of 2000 is 3W. 90% of the amplifier's cutput power is transferred to the antenna. What is the antenna power? a. 6000W b. 5400W c. 1800W d. 6666W 8. An antenna with an impedance of 1051 has a 20 Vis voltage drop. What is the antenna's power? a. 40W b. 2W c400W d. 200W 9. The transmission efficiency (u) of an AM transmitter is 0.25 and the total AM signal power (PT) is 600W. What is the carrier signal power (PC)? PC = PT - (PT x μ) a. 250W b 825W c. 150W d. 450W 10 In the equation Po= Pr- (Prx), which relates AM signal total power (Pr) to the carrier signal power (Pc). what does (Pyx p) represent? a. RF power amplifier gain b. antenna power c. sidebend power d. RF power aniplifier cutput power 1. In FM, the carrier frequency deviates with changes in what parameter(s) of the message signal? a. phase angle and amplitude b. frequency only c. amplitude only d. frequency and amplitude 2. In PM, the carrier frequency deviates with changes in what parameter(s) of the message signal? a. modulation index b. frequency only c. amplitude only d. frequency and amplitude 3 Why can a limiter circuit be used to cut off the peaks and valleys of an FM or PM signal? a. The message signal is contained in the frequency and phase deviations of the carrier, not in the amplitude variations. b. The message signal causes only small changes in the amplitude of the carrier. c. FM or PM signals do not require much transmission power d. All of the above. 4. A 4 kHz message signal causes an FM carrier signal to have a frequency deviation of ±20 kHz. What is the MI? a. 80 MI = for ffm b. 5 c. 0.2 d. 24 5. An FM camer signal with a MI of 4 contains a 3 kHz message signal. Use the table to determine the number of significant sideband pairs, and then calculate the bandwidth of the FM camer a 12 kHz b. 6 kHz c. 42 kHz d 21 kHz 1. What function does a discriminator or frequency detector perform? a. It converts FM frequency deviations into phase deviations. b. It limits the amplitude of an FM signal. c. It converts FM frequency deviations into the message signal. d. It removes the FM sum frequency from the recovered message signal. 2. What does the term quadrature mean? a a frequency difference of 45 kHz b. a phase difference of 90° c. shifting the phase of a signal d. limiting the phase difference to 45° 3. What function does the quadrature detector first perform? a. It shifts the phase of the FM center frequency by 90°. b. It filters the FM signal. c. It converts phase deviations to frequency deviations. d. It converts phase deviations to the message signal. 4. What is the quadrature detector's phase detector? a. filter b. limiter c. balanced modulator d. LC network 5. What are the output signals of the quadrature detector's phase detector? a. signals equal to half and three times the FM center frequency b. the sum frequency of the inputs and the FM center frequency c. FM signals that are 90 out of phase d. the sum frequency of the inputs and a dc voltage that varies with the message signal 1. Frequency modulation (FM) and phase modulation (PM) are subcategories of what type of modulation? a. amplitude modulation b. SSB modulation c. angle modulation d. double sideband (DSB) modulation 2. When the message signal amplitude is zero, the FM carrier signal is at what frequency? a. maximum frequency b. minimum frequency c. deviation frequency d. center frequency. For an FM signal, what does the term frequency deviation mean? a the center frequency plus the modulation percentage b. the change in frequency from the center frequency c. the modulation index times the center frequency d the message signal frequency plus or minus the center frequency 4. For commercial broadcasts, the FCC has defined 100% modulation as a positive and negative frequency change of how many kHz around the center frequency? a. 150 kHz b. 75 kHz c. two times the center frequency d. 100 kHz 5. Changes in the message signal amplitude and frequency cause frequency deviations in what type of modulation? a. PM b. AM c. FM d. SSB 6. The number of significant sideband pairs in an FM signal is a function of what parameter? a. bandwidth b. percentage of modulation c. MI d. center frequency 7. What is the function of a discriminator? a. It restores high-frequency message signals to their proper relationship with the lower frequencies. b. It recovers the message signal from frequency deviations of the FM carrier signal. c. It provides the necessary amplification and volume control for the recovered.message signal. d. It tunes the FM receiver to the desired frequency. 8. The phase shifter section of the quadrature detector shifts what FM signal frequency by 90°? a. upper sideband frequencies b. lower sideband frequencies c. center frequency d. All of the above. 9. The received FM signal has a center frequency of 95 MHz. What is the difference frequency output component of the quadrature detector's phase detector? a. 180 Mhz b. 95 Mhz c. a dc voltage d. 0 MHz 10. Why can random noise be reduced better in FM than in an AM? a FM produces less noise than AM. b. FM signal amplitude variations do not contain the message signal, so the amplitude can be limited. c. FM signals are propagated via the ionosphere d. In FM, frequency and amplitude deviations contain the message signal. "‫"الملف الثالث‬ 1. Carrier signals may have a frequency from 10 kHz to 1000 GHz. In the PROCEDURE section, you used a 1000 kHz carrier signal. What is the frequency range of message signals? a. 1 Hz to 10 Hz b. 30 Hz to 50 kHz c. 20 Hz to 20 kHz d. 100 kHz to 200 kHz EXERCISE 1-1 2. What is the process of combining a message signal with a carner signal for communication over long distances? a. amplification b. filtering c. demodulation d. modulation 5. In the PROCEDURE section, what function did the ENVELOPE DETECTOR perform? a. mixing b. amplification c. demodulation d. modulation 1. How do you adjust the frequency of the VCO-HI oscillator signal? a. by tuming the NEGATIVE SUPPLY knob on the base unit b. by inserting a two-post connector in the 1000 kHz terminals c. by turning the POSITIVE SUPPLY knob on the base unit d. by tuming the potentiometer knob on the VCO-HI circuit block. 2. How do you adjust the amplitude of the VCO-LO oscillator signal? a. by turning the NEGATIVE SUPPLY knob on the base unit b. by tuming the potentiometer knob on the MODULATOR c. by turning the POSITIVE SUPPLY knob on the base unit d. by turning the potentiometer knob on the VCO-LO circuit block 3. On the MODULATOR in the AM/SSB TRANSMITTER circuit block, how do you adjust the modulation of the carrier by the message signal? a. by turning the potentiometer knob on the MODULATOR b. by adjusting the frequency of the carrier signal c. by adjusting the frequency of the message signal d. by tuming the NEGATIVE SUPPLY knob on the base unit 4. The VCO-LO, PHASE MODULATOR, QUADRATURE DETECTOR, and PHASE- LOCKED LOOP circuit blocks are associated with what type of radio signals? a. amplitude modulated (AM) signals b. single sideband (SSB) signals c. angle modulated (FM and PM) signals d. double sideband (DSB) signals 5. On the ANALOG COMMUNICATIONS circuit board, how do you connect the AM transmitter to the AM receiver? a. A connection is not required because the signal is radiated by an antenna. b. Insert a two-post connector between R10 and the RF AMPLIFIER. c. Place switch S3 in the ON position. d. Insert a two-post connector between FROM TRANSMITTER and R8. 3. How is the carrier signal suppressed in the output of a balanced modulator? a. It is suppressed by the NEGATIVE SUPPLY voltage. b. It is suppressed by the POSITIVE SUPPLY voltage c. It is suppressed by the null potentiometer in the message signal input. d. It is suppressed by adjusting the VCO-LO potentiometer. 4. To a balanced modulator, the carrier signal is 1000 kHz and the message signal is 3 kHz. What are the sum and difference frequencies in the output? a. 997 kHz and 1003 kHz b. 994 kHz and 997 kHz c. 1003 kHz and 1006 kHz d. 994 kHz and 1006 kHz 5. When only the sum frequency is desired from a balanced modulator, what device removes the lower frequencies? a. a mixer b. a product detector c. a filter d. an automatic gain control circuit 1. A communication system requires a sender (transmitter), a transmission line or channel (frequency), and a receiver. What do you call a communication system that sends and receives information? a, unidirectional b. amplitude modulated c. frequency modulated d. bidirectional 2. What is the process of the low frequency message signal changing a characteristic of a high frequency carrier signal? a. mixing b. demodulation c. modulation d. detection 3. What do you call the frequency range of the sidebands around a carrier frequency? a. bandwidth b. message signal c. noise d. modulated frequency 4. What is the function of a product detector, quadrature detector, phase- locked loop, and envelope detector? a. modulation b. demodulation c. filtering d. mixing 5. What are the functions of the VCO-LO and VCO-HI circuit blocks? a. mixing and demodulation b. message signal generation d. phase modulation Tar c. oscillator signal generation 6. What is the function of the RF POWER AMPLIFIER and the RF AMPLIFIER? a. They increase the power level of the message signal to the speaker. b. They increase the power level of the message and carrier signals to the modulator. c. They function as the automatic gain control. d. They increase the power level of the transmitted and received signals, respectively. 7. The VCO-LO, PHASE MODULATOR, QUADRATURE DETECTOR, and PHASE- LOCKED LOOP circuit blocks possess what type of signals? a. Single Sideband (SSB) signals b. Double Sideband (DSB) signals c. Amplitude Modulated (AM) signals d. angle modulated signals 8. What is the function of a balanced modulator? a. modulation b. phase detection c. mixing d. All of the above. 9. A less than 100% modulated AM signal is output from a modulator that is not balanced. What significant output frequencies are present? a. the upper sideband, lower sideband, and carrier frequencies b. the message and carrier frequencies c. the upper sideband and lower sideband frequencies d. just the carrier 10. What device removes the Lower Sideband (LSB) from a Double Sideband (DSB) signal? a. limiter b. filter c. detector d. mixer 1. What is the function of the RF power amplifier? a. It amplifies the message signal to the AM modulator. b. It amplifies the carrier signal to the AM modulator. c. It provides the power amplification for the antenna to radiate the RF signals over long distances. d. It sets the frequency range for the antenna RF signal. 2. What is the purpose of an antenna matching network in an RF power amplifier? a. It matches the RF power amplifier's low output impedance with with the low impedance of the antenna. b. It matches the carrier and message signals, c. It matches the antenna impedance to the carrier signal frequency, d. It sets a high enough output impedance for the RF power amplifier to provide sufficient power to the low impedance antenna. 3. If the current to an RF power amplifier is 25 mArms and the input voltage is 5 Vrms, what is the amplifier input power? a. 125 mW b. 5mW c. 30 mW d. 1.25 mW 4. If the RF power amplifier input power is 2W and the output power to the antenna matching network is 5000W, what is the power gain? a. 10,000 b. 2500 c. 5002 d. 1000 5. If the total AM signal power (Pr) to the antenna is 5000W and the antenna carrier power (Pc) is 3400W, what is the antenna sideband power (Psa)? a. 8400W b. 1600W c. 800W d. 3200W 1. If the message signal to an amplitude modulator is a voice signal, the envelope of the AM signal will have what type of waveform? a, sine waveform b. square waveform c. triangular waveform d. an irregular waveform 2. If a 3 kHz message signal modulates an 800 kHz carrier signal, what frequencies are contained in the AM radio signal? a. 797 kHz, 800 kHz, and 803 kHz b. 3 kHz and 800 kHz c. 800 kHz and 803 kHz d. 797 kHz and 803 kHz 4. If the sideband power (PSB) of an AM signal is 3.3W and the total power (PT) is 10W, what is the transmission efficiency (u)? a. 3.03 b. 0.67 c. 0.33 d. 0.49 5. In AM transmission, what is the optimum percentage of modulation? a. 33% b. 100% c. 66% d. 150% 6. If the antenna matching network of an RF power amplifier is adjusted to an impedance of 6502, and if the antenna impedance is 500, what is the output impedance of the RF amplifier? 8. 7000 b. 6000 c. 6500 d. 500 7. The input power to an RF power amplifier with a gain of 2000 is 3W. 90% of the amplifier's output power is transferred to the antenna. What is the antenna power? a. 6000W b. 5400W c. 1800W d. 6666W 8. An antenna with an impedance of 100 has a 20 Vims voltage drop. What is the antenna's power? a. 40W b. 2W c. 400W d. 200W 9. The transmission efficiency (µ) of an AM transmitter is 0.25 and the total AM signal power (PT) is 600W. What is the carrier signal power (PC)? PC = PT - (PT x μ) a. 250W b. 625W c. 150W d. 450W 10.In the equation Pc = Pr - (Prx μ), which relates AM signal total power (PT) to the carrier signal power (Pc), what does (Prx µ) represent? a. RF power amplifier gain b. antenna power c. sideband power d. RF power amplifier output power 1. When the RF filter (an LC circuit) is tuned for an AM frequency, what relationship is true at the resonant frequency (f.)? a. The inductive reactance (X₁) equals the resistor impedance. b. X equals the capacitive reactance (Xc). c. The AM signal's USB and LSB frequencies are equal. d. The carrier signal cancels the message signal. 2. Commercial AM broadcasting stations, which usually are in the frequency range from 540 kHz to 1600 kHz, have a 10 kHz bandwidth. In an AM radio, the RF filter must have a bandwidth greater than what frequency range? a. 1600 kHz b. 540 kHz c. 1060 kHz d. 10 kHz 3. The RF amplifier circuit has an RLC network in the Q3 collector circuit Why is it necessary to tune this RLC circuit for the frequency selected by the RF filter? a. to adjust the bandwidth of the RF filter b. to select the AM signal frequency c. to maximize the gain of the RF amplifier d. to eliminate noise in the amplified AM signal 4. The AM signal power at the RF stage input is -90 dBm, and the RF stage output power is -20 dBm. What is the power gain of the RF stage? a. 70 dB b. -70 dB c. 110 dB d. 1800 dB 5. At the RF amplifier output, the carrier signal is 250 mVrms (VR)), and the output impedance is 3 ΚΩ (R). What is the rms power of the carrier signal (PRF()) at the RF amplifier output? PRF(0) = VRF(0)/R a. 20.8 mW b. 20.8 μW c. 83.3 mW d. 83.3 pW ______ "‫___________"خلصت الحكاية‬