2. Definition:
Continuous waves(CW) are electromagnetic
waves that have a fixed frequency and
amplitude, usually of a sinusoidal wave.
A simple CW transmitter and receiver uses
continuous waves to transmit and receive
radio frequency(RF) signals.
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3. Components:
A very simple CW tranceiver(transmitter and
receiver) consists of a RF amplifier, a
detector and an audio amplifier.
Detector stage also consists of a frequency
oscillator.
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4. Working:
The transmission of CW is basically done by switching on and off
of the RF signal source/power.
Power supply is alternated to various stages of the device, this is
known as "Keyeing".
Keyeing can be done to oscillator, amplifier or the driver stage.
Usually done to driver stage.
The detector stage consists of a "beat frequency oscillator(BFO),
which produces a local RF signal(continued next slide).
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5. Working(continuation):
This local signal is "mixed in" with the received RF signal,
differential signal is taken as output. Output is then passed onto
final stage.
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6. Working (applicative):
This simple functioning can be used further, for example in
the form of a CW radar.
Transmits RF signal to an object, then receives the
bounced back signal to determine further properties of
said object. This is done by application
of the Doppler effect.
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7. Doppler Effect:
Doppler effect is a phenomenon where frequency of an electromagnetic wave changes
in accordance to the motion of the source of said EM wave.
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8. Application:
Semi-Active Radar Homing(SARH) air-to-air missile.
Object detection technology
Velocity measuring devices(used by traffic police, in
sports such as NASCAR and tennis).
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