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20 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What is a Deviation rate? |
The frequency of the modulating signal determines the deviation rate. |
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What is the definition of FM and AM?
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Frequency modulation and amplitude modulation.
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What is phase modulation(pm)? |
A modulation pattern that encodes information as variations in the instantaneous phase of the carrier. |
When the amount of phase shift of a constant frequency carrier is varied in accordance with a modulating signal, the resulting output is phase modulation |
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What is a varactor?
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diode, changing the width of the depletion region, an amount of bias on the diode.
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What is a crystal oscillator? Why do we use them?
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Accurate.
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What is a frequency multiplier?
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A circuit with an output frequency that is some integer multiple of the input frequency
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What are the components of a PLL? |
A control system that generates an output signal whose phase is related to the phase of the input signal. |
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What is a voltage controlled oscillator(VCO)?
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Oscillators whose frequencies are controlled by an external input voltage are called vcos.
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What is a frequency demodulator? (as opposed to a frequency modulator)
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A circuit used to recover the original modulating signal from an FM transmission
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What is the modulation index?
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The ratio of the frequency deviation to the modulating frequency. (mf=fd/fm)
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What are the benefits of FM over AM?
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FM is superior due to fm noise immunity,capture effect, transmitter efficiency, and fm has greater bandwidth.
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What is the definition of noise?
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Noise is interference generated by lightning, motors, transient signals, automotive ignition systems, etc.
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What are the drawbacks of FM over AM?
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FM requires complex circuitry and exccesive spectrum use.
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What are bessel functions?
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Complex mathematcal processes. (Vfm)
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What type of circuits are used to recover FM signals?
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discriminators.
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What is a collpits oscillator?
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The feedback is derived from a capacitive voltage divider.
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What is a crystal oscillator?
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The frequency of the AC output is determined by the mechanical properties of a piezoelectric crystal.
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What is a hartley oscillator?
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The frequency is determined by a tuned circuit consisting of capacitors and inductors.
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What is armstrong oscillator?
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An electronic oscillator circuit which uses an inductor and capacitor to determine the oscillation frequency; an LC oscillator.
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What is a frequency deviation? |
The amount of change in carrier frequency produced by the modulating signal. |
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