RF Electronics Chapter 5: Frequency Mixers Page 134
2022, C. J. Kikkert, James Cook University, ISBN 978-0-6486803-9-0.
Figure 5.37. IF voltage of figure 5.36 with frequency components >25 MHz removed.
Figure 5.38. RF spectrum of a double balanced diode mixer as an up-converter.
Figure 5.38 shows the RF spectrum of a DBM as an up-converter. The relationship
between the spectral components and LO and IF frequencies are shown in table 5.1.The
desired spectrum around the 105 MHz LO is near ideal and shows no unwanted spectral
components above -65 dBm. Figure 5.39 shows the corresponding RF voltage. The
spectrum and the waveform are very similar to that for an ideal multiplier, shown in
figures 5.8 and 5.10. Note the 180º phase change in the waveforms at times t=0.05 and
0.15 µs and the near constant amplitude of the RF voltage as the LO level is changed.
This shows the mixer has a very low sensitivity to LO AM noise.
RF Electronics: Design and Simulation
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