Description : What is the function of the oscillator in a cw transmitter?
Last Answer : It generates an rf carrier at a given frequency within required limits.
Description : State the method used to increase the speed of keying in a cw transmitter.
Last Answer : Machine keying.
Description : In a radio transmitter, the frequency of the crystal oscillator will be stable for a long time if the quality factor of the crystal resonator is (a) > 100 (b) > 500 (c) > 1000 (d) > 20000
Last Answer : In a radio transmitter, the frequency of the crystal oscillator will be stable for a long time if the quality factor of the crystal resonator is > 1000
Description : When a transmitter uses a high-power oscillator to produce the output pulse, what switches the oscillator on and off?
Last Answer : High-voltage pulse from the modulator.
Last Answer : Antenna-to-ground capacitance can cause the oscillator frequency to vary.
Description : In an fm transmitter, when does an oscillator generate only a steady frequency?
Last Answer : When no modulation is present.
Description : An oscillator that uses crystal control should be A) Frequency stable B) useful only at low frequencies C) AVFO D) none of the above.
Last Answer : A) Frequency stable
Description : Name three advantages of cw transmission
Last Answer : A high degree of clarity even under severe noise conditions, long-range operation, and narrow bandwidth.
Description : What are the three requirements for cw transmission?
Last Answer : A method of generating oscillations, a method of turning the oscillations on and off (keying), and an antenna to radiate the energy.
Description : What principle is used to help distinguish between two cw signals that are close in frequency?
Last Answer : Heterodyning.
Description : One of the following is a possible cause for a slow drift of frequency in a self-exited transmitter oscillator circuits resulting to a poor frequency stability. A. Loose shielding B. ... capacitor in the oscillator C. Poor soldered connections D. Faulty capacitor, resistor, tubes or resistors
Last Answer : B. Heating of capacitor in the oscillator
Description : How do you eliminate radio frequency variation of an oscillator transmitter caused by its supply voltage? A. Use new power supply B. Lossen power supply shielding C. Use of regulated power supply D. Use of high capacitor in the supply circuit
Last Answer : C. Use of regulated power supply
Description : One of the following is a high powered RF ac basic transmitter that has two or more stages, the oscillator stage which determines the frequency opereation and RF amplifier stage orstages that develop the ... to develop a good frequency stability. A. Goldsmith B. MOPA C. Alexanderson D. Hartley
Last Answer : B. MOPA
Description : One of the following is a possible cause of an abrupt frequency variation in a self exited transmitter oscillator circuits resulting to a poor frequency stability to hold a constant frequency ... capacitor in the oscillator D. Loose connections in the oscillator, amplifier, or antenna circuits.
Last Answer : D. Loose connections in the oscillator, amplifier, or antenna circuits.
Description : Which of the following is one of the possible causes for a slow drift of frequency in a self exited transmitter oscillator circuits resulting to a poor frequency stability? A. Poor soldered connections ... , or antenna circuits D. DC and RF heating of resistors, causing then to change values.
Last Answer : D. DC and RF heating of resistors, causing then to change values.
Last Answer : The crystal oscillator frequency is very stable due to High Q of the crystal.
Description : Which oscillator uses tapped capacitors for feedback?
Last Answer : Colpitts.
Description : Which oscillator uses a tapped inductor for feedback?
Last Answer : Hartley.
Description : Which oscillator uses a tickler coil for feedback?
Last Answer : Armstrong.
Description : How does heterodyning distinguish between cw signals?
Last Answer : By giving a different beat frequency for each signal.
Description : What are the essential components of a cw receiver system?
Last Answer : An antenna, tank circuit for tuning, rectifier for detection, filter to give constant output, and an indicator device
Description : In a heterodyne-type frequency meter, what is the difference between the oscillator frequency and the unknown frequency?
Last Answer : Beat frequency.
Description : What determines the frequency of a tunnel-diode oscillator?
Last Answer : The tuned circuit or cavity frequency.
Description : What signal is used to synchronize the coherent oscillator to a fixed phase relationship with the transmitted pulse?
Last Answer : Coho lock pulse.
Description : Why is a high-gain transistor used in the phase-shift oscillator?
Last Answer : Because of the losses encountered in the RC networks.
Description : Which components provide the regenerative feedback signal in the phase-shift oscillator?
Last Answer : Resistor-capacitor networks.
Description : What is the result of an impedance mismatch between a receiver or transmitter and its transmission line or antenna?
Last Answer : High vswr, which equates to poor reception or a loss of power output.
Description : All the power sent down a transmission line from a transmitter can be transferred to an antenna under what optimum conditions?
Last Answer : When the characteristic impedance of the transmission line and the load impedance are equal.
Description : What term is used for the end of the transmission line that is connected to a transmitter?
Last Answer : Input end, generator end, transmitter end, sending end, and source.
Description : The ratio of the level of the modulated output of a transmitter under conditions of standard test modulation to the level of the demodulated output with no modulation applied both measured with the ... . Reference audio output B. None of these C. Audio frequency response D. Residual noise level
Last Answer : D. Residual noise level
Description : What transmission method does NOT depend on relative frequency or target motion?
Last Answer : Pulse modulation.
Description : What factor determines the difference between the transmitted frequency and the received frequency in an fm transmitter?
Last Answer : Travel time.
Description : The beat frequency in a swept-frequency transmitter provides what contact information?
Last Answer : Range.
Description : What is the purpose of frequency-multiplier stages in a VHF transmitter?
Last Answer : To raise the low frequency of a stable oscillator to the vhf range.
Description : Type of emission produced by one of the early radio transmitter in trains of damped RF ac waves where its oscillator is coupled to a long wire antenna, normally used in radio telegraph and having sidebands on its carrier. A. Digital emission B. Key emission C. Cycle emission D. Spark emission
Last Answer : D. Spark emission
Description : The stability of transmitted signal from a simple Hartley oscillator single transmitter which is coupled to and antenna wire affected by ______. A. Chirping of oscillator B. Closer coupling between the oscillator and the antenna. C. Location of antenna D. Material of antenna
Last Answer : B. Closer coupling between the oscillator and the antenna.
Description : Draw the labeled circuit of RC phase shift oscillator. State the formula for frequency of oscillator.
Last Answer : Frequency of oscillation is given by,
Description : The speed of a three-phase squirrel-cage induction-type motor operating in a fixed frequency system is varied by changing the _____________. A. number of phases to the motor B. number of stator poles C. locked rotor current D. resistance of the rotor winding
Last Answer : Answer: B
Description : It is an average power of a radio transmitter supplied to the antenna transmission line taken during a long sufficient interval of time and compared with the lowest frequency encountered in the modulation ... operating conditions. A. Carrier power B. Rated power C. Mean power D. Peak envelop power
Last Answer : C. Mean power
Description : Referred to as an average power from the radio transmitter supplied to the antenna transmission line taken during one radio frequency cycle under no modulation. A. Carrier power B. Rated power C. Peak envelop power D. Mean power
Last Answer : A. Carrier power
Description : Average power of a radio transmitter supplied to the antenna transmission line by a transmitter during one radio frequency cycle taken under the condition of no modulation. A. Peak envelop power B. Rated power C. Carrier power D. Mean power
Last Answer : C. Carrier power
Description : The width of the frequency band which is just sufficient to ensure the transmission of information at the rate and with the quality required under a specified condition and class of emission. A. Occupied bandwidth B. Reference frequency C. Necessary bandwidth D. Frequency tolerance bandwidth
Last Answer : C. Necessary bandwidth
Description : What component in a blocking oscillator controls pulse width?
Last Answer : Transformer.
Description : What is the primary advantage of power-amplifier transmitters over keyed-oscillator transmitters?
Last Answer : Frequency stability.
Description : Name a disadvantage of sine-wave oscillator synchronizers.
Last Answer : It requires additional shaping circuits.
Description : What basic circuits meet the requirements of an externally synchronized master oscillator?
Last Answer : Sine-wave oscillator, single-swing blocking oscillator, and master trigger (astable) multivibrator.
Last Answer : . It requires additional shaping circuits.
Description : What type of multivibrator can be used as a radar master oscillator?
Last Answer : Free-running.