Frequency Hopping; Key Signals - Analog Devices ADRV9005 Reference Manual

Reference Manual ADRV9001

FREQUENCY HOPPING

Before delving into the frequency hopping feature details, read the Multichip Synchronization and Timing Parameters Control sections of this
document.
In the ADRV9001, FH is mainly designed for TDD applications. It allows to quickly switch radio signals among different frequency channels at
different times. Figure 103 shows the high-level concept of FH.
Figure 103. High-level Concept of Frequency Hopping
Figure 103 shows that different frequencies are used at different time slots. FH provides the benefit of high resistance to narrowband
interference and strong capability in combating malicious interception and jamming. In addition, FH signals can easily share the bandwidth with
other conventional communications due to the minimal mutual interference, resulting in high spectrum efficiency. With an increased hop rate
and a larger set of frequency sub-bands, the advantages of FH become more prominent, which makes it an attractive solution for many different
applications.
The ADRV9001 provides advanced FH capability through its unique and flexible PLL design, i.e., instead of having one dedicated PLL for the
receive datapath and one for the transmit datapath as many other transceivers, the device employs two RF PLLs, and both PLLs can optionally
source any receiver or transmitter, or both, or neither. This flexibility is essential for the ADRV9001 to support FH in various TDD applications
such as single-channel and dual-channel operations including transmit-only mode (1T/2T), receive-only mode (1R/2R), and transmit and
receive mode (1T1R/2T2R). Both channel diversity and channel multiplexing are supported for the dual-channel operations.
FH capability is achieved by retuning the PLLs before switching to the new frequency. There are different FH modes based on the method
of using the two PLLs. One method is to ping pong between the two PLLs, which means while one PLL is being used for on-air signal
transmission or reception on one frequency, the other PLL is retuned to prepare for the next frequency. This makes FH very fast. Another
method is to use only one PLL for a pair of Tx/Rx channel for FH. When one hopping frame ends, the same PLL retunes to the new frequency.
Therefore, it is possible to hop two pairs of channels (Rx1/Tx1 and Rx2/Tx2) separately by using two different PLLs.

KEY SIGNALS

To understand FH operations in the ADRV9001, it is crucial to first understand several key signals the BBIC needs to set up such as "HOP", "Tx
Setup", and "Rx Setup" signals.
analog.com Rev. A | 116 of 377