3 LOCAL OSCILLATOR
In the first local oscillator, instead of the conventional PLL/VCO system, a
*1 Reciprocal mixing: First, the signal sourced from a signal generator (SG) at a frequency far from the receive frequency is injected. Then, the output level of the signal generator is changed to measure the level at which the signal is detected as noise. The higher the value, the lower the noise that is produced due to adjacent undesired signals occurring and therefore quieter reception is possible.
Figure 3-1 Comparison: C/N Characteristics
Figure
For example, at the 10 kHz point, if the receive frequency is 14.200 MHz, an unmodulated carrier signal of 14.210 MHz is supplied from a signal generator to the antenna terminal of the transceiver.
In the
Figure
C/N characteristics of the first local oscillator when receiving 14.2 MHz
1 kHz | ||
10 kHz | ||
100 kHz | ||
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CONTENTS |
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