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 : 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
Last Answer : The crystal oscillator frequency is very stable due to High Q of the crystal.
Description : What transmission method uses a stable cw reference oscillator, which is locked in phase with the transmitter frequency?
Last Answer : Pulse-Doppler.
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 : 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 : A radio transmitter is an equipment:
Last Answer : A radio transmitter is an equipment: for generating modulated radio frequency waves
Description : Refer to the deviation of the operating frequency of a crystal oscillator from its nominal value due to temperature variations. A. Drift B. Flash over C. Frequency deviation D. Deviation ratio
Last Answer : A. Drift
Description : Six (6) MHz crystal oscillator has a stability of 1 part in 106. The largest frequency error expected of this crystals A) 0.06 Hz B) 0.6 Hz C) 6 Hz D) 60 Hz.
Last Answer : C) 6 Hz
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 : 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.
Description : In an fm transmitter, when does an oscillator generate only a steady frequency?
Last Answer : When no modulation is present.
Description : The frequency range of FM radio is
Last Answer : The frequency range of FM radio is 88MHz to 108MHz
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 : A superheterodyne radio receiver with an IF of 455KHZ is turned to 1000KHZ. Find: (i) Image frequency (ii) Local oscillator frequency
Last Answer : Given Intermediate Frequency fi=455KHz Signal frequency =fs=1000KHz Local oscillator frequency fo=fs+fi Fo=1000KHz+455KHz =1455KHz Image frequency is the input frequency which produces the same intermediate frequency fsi=fs+2fi =1000KHz+2*455KHz =1910KHz
Description : What is Miller crystal oscillator? Explain its operation.
Last Answer : It is nothing but a Hartley oscillator its feedback Network is replaced by a crystal. Crystal normally generate higher frequency reactance due to the miller capacitance are in effect between the transistor terminal.
Description : State the basic principle of piezoelectric crystal and draw the circuit diagram of crystal oscillator.
Last Answer : Basic Principle: The main principle of a piezoelectric crystal is that a mechanical force, when applied on the crystal, it vibrates and produces electric charges on the crystal surface. When ac voltage is applied across crystal, it vibrates at the frequency of the applied voltage. (OR)
Description : Compare between RC phase shift oscillator and crystal oscillator.
Last Answer : RC phase shift oscillator Crystal oscillator This oscillator is used for low frequency range. Quartz crystal is mainly used in radio-frequency (RF) oscillators Used resistor and capacitor ... RC network is used as feedback network. Crystal is connected in feedback.
Description : crystal oscillator and its applications.
Last Answer : Need: Any circuit that generates an alternating voltage is called an oscillator. To generate ac Voltage, it takes energy from the dc source. 1. In some applications voltages of low frequency are required where ... generate clock in digital systems. It is used as sweep circuits in TV and CRO.
Description : List the applications of RC oscillator and crystal oscillator.
Last Answer : Applications of RC oscillator : 1) In AF signal generators 2) In radio transmitter & Receivers 3) Sine wave generator. Applications of Crystal oscillator : 1) Electronic navigation systems 2) Frequency Synthesizers 3) Timing circuits (Clock) with high stability. 4) RADAR systems.
Description : Draw the circuit diagram of crystal oscillator and explain its working.
Last Answer : To excite a crystal for operation in the series-resonant mode it may be connected as a series element in a feedback path, the crystal impedance is the smallest and the amount of positive feedback is the largest. ... which is good. The resonant frequency is given as Fo = 1/( 2 π √LC )
Last Answer : The main advantage of crystal oscillator is that its output is: A Constant frequency range
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 : 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.
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 : What would happen if you plugged an FM transmitter into a radio's headphone jack and set the radio to the transmitter's transmitting frequency?
Last Answer : You would get a positive feedback loop, probably resulting in an audible tone. The amplitude would be limited by the transmitter’s modulation limiter, so all you’d have is a very ordinary oscillator.
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 : Feedback factor at the frequency of oscillation of a Wien bridge oscillator is: (1) 3 (2) 1/3 (3) 1/29 (4) 3/29
Last Answer : Feedback factor at the frequency of oscillation of a Wien bridge oscillator is: 1/3.
Description : What factor determines the difference between the transmitted frequency and the received frequency in an fm transmitter?
Last Answer : Travel time.
Description : The most common device used for detection in radio receivers is (A)amplifier (B) triode (C) diode (D) transistor
Last Answer : The most common device used for detection in radio receivers is diode
Description : A radio receiver is placed at one corner of a table and again placed at some other corner of the same table. Loudspeaker output is changed because (a) image interference is reduced (b) adjacent channel interference is increased (c) of fading (d) line of sight propagation is not utilized
Last Answer : A radio receiver is placed at one corner of a table and again placed at some other corner of the same table. Loudspeaker output is changed because of fading
Description : The basic element of radio communication system which generates radio waves is 1. micro phone 2. transmitter 3.transmitting antenna 4. Loudspeaker
Last Answer : The basic element of radio communication system which generates radio waves is transmitter
Description : Describe the functions of mixer and local oscillator in radio receiver
Last Answer : Frequency Mixer:- The function of frequency mixer is to heterodyne signal frequency fs and local oscillator frequency fo. At the output, it produces the difference frequency known as ... local oscillator frequency fo is then mixed with incoming frequency to give intermediate frequency.
Description : The Ku frequency band used in satellite communication (for uplink and downlink) is: (1) 14 GHz and 11 GHz (2) 30 GHz and 20 GHz (3) 70 GHz and 50 GHz (4) 60 GHz and 45 GHz
Last Answer : The Ku frequency band used in satellite communication (for uplink and downlink) is: 14 GHz and 11 GHz
Description : In a PCM system the number of quantization level are 16 and the maximum signal frequency is 4 KHz the transmission bit rate is
Last Answer : In a PCM system the number of quantization level are 16 and the maximum signal frequency is 4 KHz the transmission bit rate is 32 Kbits/sec
Description : The frequency range 30MHz - 300MHz is (A) medium frequency (B) very high frequency (C) super high frequency (D) Infrared frequency
Last Answer : The frequency range 30MHz - 300MHz is very high frequency
Description : In commercial FM broadcasting, the maximum frequency deviation is normally (A) 5 KHz (B) 15 KHz (C) 75 KHz (D) 200 KHz
Last Answer : In commercial FM broadcasting, the maximum frequency deviation is normally 75 KHz
Description : A rectangular waveguide is 4.2 cm by 1.85 cm. The cut-off frequency of the dominant mode through this waveguide is (a) 3.57 GHz (b) 3.75 GHz (c) 3.70 MHz (d) 3.57 MHz
Last Answer : A rectangular waveguide is 4.2 cm by 1.85 cm. The cut-off frequency of the dominant mode through this waveguide is 3.57 GHz
Description : For an antenna to be frequency-independent, it should expand or contract in proportion to the (a) gain (b) directivity (c) wavelength (d) impedance
Last Answer : For an antenna to be frequency-independent, it should expand or contract in proportion to the impedance
Description : A tuned circuit has a Q of 100 at its resonant frequency of 500 kHz. Its bandwidth is _____kHz. (A) 50000 (B) 0.2 (C) 600 (D) 5
Last Answer : A tuned circuit has a Q of 100 at its resonant frequency of 500 kHz. Its bandwidth is 5 kHz.
Description : The signal is extended from 96KHz to 100KHz, so the minimum sampling frequency required is (a) 8KHz (b) 200KHz (c) 4KHz (d) 100KHz
Last Answer : 200KHZ
Last Answer : If a wave has frequency of 2 Hz, it has a period of 1/2 s.
Last Answer : In CCIR system B standard, the line frequency 15,625 lines/sec.
Last Answer : The maximum Usable Frequency is dependent on the electron density of the ionospheric layer.
Last Answer : In the telephone, the dial tone has a frequency of 33 Hz.
Description : Which of the following parts of the radio receiver represent the component that extracts the desire RF signal from the electromagnetic wave? A. AF amplifier B. Antenna C. Detector D. Crystal
Last Answer : B. Antenna
Description : What is the local oscillator (mixer) frequency of the satellite with an uplink frequency in GHz band? A. 3500 MHz B. 4500 MHz C. 2225 MHz D. 2555 MHz
Last Answer : C. 2225 MHz
Description : When measuring a transmitter’s frequency against a suitable standard, the frequency to be measured is taken from the A. oscillator stage B. intermediate amplifier C. buffer stage D. final RF stage
Last Answer : D. final RF stage