Learning Event 2
DESCRIBE AND IDENTIFY THE CHARACTERISTICS OF AM RADIO
AM radio signal. The AM signal is one of the first kinds of transmission of radio signals. The
information being broadcast by the station is varied in step with the amplifier of the transmitted signal.
This type of system is what we know today as the superheterodyne radio.
a. The superheterodyne radio has several particular functions (fig 4-2). All of the functions are
similar regardless of the components used in the radio. Therefore, whither the radio was a transistor
solid-state or a vacuum-tube type, they both use the same functional diagram. We can go on to say that
the electronic signal received from the transmitting source or station are processed the same whether the
radio is transistorized or vacuum tube.
Figure 4-3. The AM radio block diagram
b. The AM superheterodyne radio works by a transmitted signal which is picked up by the
antenna, processed through the set to the speaker as follows:
(1) The main purpose of the antenna is to pick up a broadcast signal and take that signal into
the receiver for processing into sound waves.
(2) The "radio frequency amplifier" does what its name says. This amplifier is designed to
operate in the radio frequency range. The amplifier provides for tuning or selecting a specific frequency
and it amplifies the signal receiver in this frequency. The output goes to the mixer block.