Preliminary Technical Data UG-1828
Rev. PrC | Page 243 of 338
Figure 230. Tx1/Tx2 Return Loss
Figure 231. Tx1/Tx2 Insertion Loss, Simulated
EXTERNAL LO PORT IMPEDANCE MATCHING NETWORK
External LO1 and LO2 PORT can be used for injecting LO signal with very high spectral purity for internal receivers and transmitters. RF
matching network for these ports would be implemented on single-ended and differential sides of balun to reduce insertion loss due to
reflections at the desired LO frequency. Method of obtaining matching network is similar to RX and TX port matching. Depending on the
selected divide ratio of ADRV9001 external LO input frequency divider SPI register setting, a band of frequency in which external LO
matching network need to operate should be correctly derived by the division ratio chosen.
EXT LO Inputs
Unlike the internal synthesizers that always operate from 6 – 12 GHz regardless of the RF tune frequency, when an external LO pins are
used the frequency applied must be a multiple of 2 times(i.e. 2x,4x,8x, and so on) of the desired RF signal channel frequency. The LO
input signal is internally divided by a series of dividers to generate the required LO quadrature relationship at desired RF frequency of
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