35
The SGC Building, 13737 S.E. 26th St. Bellevue, Washington 98005 USA
P.O. Box 3526, 98009 Tel: (425) 746-6310 Fax: (425) 746-6384
© 1997 SGC Inc.
When Morse code is being sent, the transmitting portion of the transceiver is being keyed on and off. Your
transmitter could produce no sound or an unpleasant sound. As a result, most transceivers contain built-in sidetone
oscillators, which produce a more pleasant and easily copied tone during CW operation.
The filters in a radio control the amount of the radio spectrum that can be received at
once; this amount of spectrum that you hear is known as the passband. For high-fidelity
shortwave broadcasts in the AM mode, filters that are between 8 and 15 kHz wide are used;
for general or weak-signal listening, filters that are between 2 and 6 kHz wide are used; for
CW signals, filters that are between 0.5 and 2 kHz wide are used. The cut-off shape of the
filter is also very important. If the filters cut out an exact portion of the band, they are operating properly. However,
less-expensive filters allow more of the adjacent-channel "slop" to be received. The filters are one of the most
important features in a receiver or in the receiving portion of a transceiver.
Digital signal processing (DSP) is a technology that is rapidly revolutionizing all aspects of the electronics
industry. Digital signal processing, will probably revolutionize at least some aspects of this world. DSP may have
much the same effect that personal computers had on everyday life in the early 1980's (in part because DSPs are
computer-related).
DSPs are effective in many different configurations and applications (such as in medical electronics, diesel
engine tune-ups, speech processing, long-distance telephone calls, music processing and recording, and television
and video enhancement).
Filters control the
amount of radio
frequency spectrum
that can be
received at once:
The Passband.
SIDETONE
FILTERS
DSP (DIGITAL SIGNAL PROCESSING)
To Next Page