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31 - �� ������������ � ��������� 2

For reinforcement, let us look at Figure 31-7, the output of the balanced modulator
on each sideband. Remember, for either sideband to get through the sideband filter,
the centre of the sideband must be on 7MHz or 7000kHz. On USB the carrier is on
the lowest extremity of the sideband. For LSB the carrier is on the highest extremity
of the sideband. With the carrier oscillator on 6998.5kHz the USB passes through
the sideband filter. When the carrier oscillator is switched to 7001.5kHz, the LSB
passes through the sideband filter. In each case, the unwanted sideband is blocked
by the crystal filter.

Figure 31-7 Bandpass (sideband) filter passes the wanted sideband.

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