Tips On Radio Waves - Sony Walkman ICF-SW7600GR Operating Instructions Manual

Tips on radio waves

What is SSB (Single Side Band)?
SSB is very popular among ham and business radio transmissions,
and is commonly used in many amateur bands because of its
superiority in signal intelligibility. Its impressive signal intelligibility
is achieved with minimum interferences when compared to DSB
(Double Side Band) owing to its half bandwidth structure.
In general, SSB transmissions employ the USB (Upper Side Band)
modulation, while amateur band transmissions below 10 MHz
employ the LSB (Lower Side Band) modulation.
Conventional radios without a BFO
Carrier
Amplitude
(Beat Frequency Oscillator) circuit
cannot receive SSB transmissions
LSB USB
successfully. This unit can receive
SSB transmissions successfully with
the built-in BFO (Beat Frequency
Frequency
Oscillator) circuit.
What is CW (Continuous Wave)?
CW is also popular among ham and business radio transmissions.
Unlike other signals, the amplitude of a carrier is not modulated for
CW transmissions. CW transmissions convey information by
interrupting the carrier and use Morse code as a means of
communication.
This unit can receive CW transmissions successfully with the built-in
BFO (Beat Frequency Oscillator) circuit as beat sound only. To fully
comprehend the information transmitted by CW transmissions, an
understanding of the Morse code is prerequisite.
What is synchronous detection?
There are two underlying obstacles in optimum AM reception:
distortions due to fading and interferences from adjacent broadcast
stations.
Synchronous detection is effective in solving these obstacles.
Distortions due to fading are generally caused by over-modulation
which occurs when a carrier component of the received signal is
attenuated along the way. The synchronous detection circuit of this
unit generates a pure carrier frequency with no level variation which
is ideally synchronized with the original carrier to compensate for
the attenuated carrier component, thus dramatically reducing
distortion.
Likewise, AM (LW, MW, and SW) broadcast generally employs DSB
(Double Side Band) signals for transmissions in which the modulated
signals are transmitted using both the upper and lower side bands
(USB and LSB). In most cases, one of the side bands is affected by
interferences from adjacent broadcast stations (i.e., beats). The
synchronous detection circuit of this unit extracts one of the two
sides (USB or LSB) of the DSB
(Double Side Band) signal which is
Carrier
Interference
free from interferences. This allows
LSB USB
clear reception without the
interferences from adjacent broadcast
stations.
Only this side is received.
41 GB
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