| 摘要 |
<p>PURPOSE: To minimize the level of carrier waves at the time at switching the frequency and to reduce the spread of noise spectrum at the time of switching the frequency by passing the frequency switching signals of rectangular waves through a low-pass filter and generating amplitude limiting signals. CONSTITUTION: Plural pieces ofΔθwhich are frequency set values are stored in a frequency table 1 beforehand. The frequency table 1 judges the level rise of the frequency switching signals 100 as a frequency switching timing, successively selects one from the pluralΔθand outputs theΔθ. Thus, the frequency is switched by the rise of the frequency switching signals 100. The frequency switching signals 100 are shaped into the amplitude limiting signals 105 in the low-pass filter 5 and supplied to the reference input terminal of a digital/analog converter 4. That is, by turning the amplitude limiting signals 105 to the reference level signals of the digital/analog converter 4, the amplitude of the carrier waves 104 is limited only at the time of switching the frequency and the spread of the noise spectrums is reduced.</p> |
