Analog Devices ADRV9005 Reference Manual page 133

Reference Manual ADRV9001
FREQUENCY HOPPING
Figure 125. Rx Only with Long Propagation Delay with PLL Mux Mode
Transmitter Only with Long Propagation Delay
The ADRV9001 also supports the transmitter only case, where the propagation delay is greater than the duration of a hop frame.
To achieve this, specify a parameter as a part of the FH configuration to delay the powering up of the transmitter analog in terms of hop frames.
Then time the enabling of the interface, along with using the "txRiseToAnalogOn" timing parameters, to fine-tune the delay.
The delay parameter specifies the delay in terms of hop frames after the first transmitter setup rising edge is received. By design, the
ADRV9001 enforces a minimum delay for both the transmitter and receiver of 1 in the PLL Mux mode. However, for transmitter only, this delay
can be greater than 1. If set to 0, the ADRV9001 defaults the delay to 1.
After the first transmitter setup rising edge, then continuously send a pulse train of transmitter setup signals until the hop edge, in which
the transmitter frame begins on air. After this, maintain any number of consecutive transmitter frames, as long as the transmitter setup is
continuously toggled. After the pulse train of transmitter setup stops (meaning a hop edge without a preceding transmitter setup rising edge),
the transmitter channel is powered down at the next hop edge. A subsequent transmitter setup begins the process again.
This example shows a four-frame delay, with the transmitter frame starting on air at the fifth frame after the first transmitter setup rising edge.
To account for the transition period between the consecutive frames, pad the valid data with guard symbols. These are marked by the gray
boxes, as shown in Figure 126. Also, pad the data to keep the transition and dwell times consistent. This is because the transition required for
the first transmitter frame is greater than for consecutive frames.
There is also the option to program the "riseToAnalogOn" timing parameter to 0, indicating the analog power-up can be powered up
immediately after the hop edge. Then, time the data to the antenna based on when the transmitter setup rising edge is dropped and start
transmitting data.
For the PLL Mux mode, the transmitter setup falling edge marks the beginning of the interface. "txAnalogPowerOnFrameDelay" starts to
decrease from the original value when the hop signal first samples a high of the transmitter setup signal until it is decreased to 0. When
reaching 0, it waits another frame before the transmitter analog is powered on due to the 1 frame delay in the PLL Mux mode. The value
remains 0 until the transmitter setup is sampled with low, and the value then sets back to the original value.
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