Analog Devices ADRV9001 User Manual page 76

UG-1828
decision if full or partial of the guard data should be received and it is the user's responsibility to make sure that the guard data usage is
compliant with the standard requirement. The RX_ENABLE pin is controlled by the user to signal ADRV9001 the start and end of a
receive burst at the air (Note RX_ENABLE should rise before the start of the receive burst at air to allow powering up analog front end.).
Based on the RX_ENABLE signal and a set of receive timing parameters configured by the user, ADRV9001 further controls receive
analog components, receive interface, and the external LNA (if it is controlled by ADRV9001 instead of user) to make sure that the
received burst is sent to BBIC at the deterministic time as desired by user.
Similar to transmit timing parameters, as shown in Figure 63, receive timing parameters can be categorized into three types: ADRV9001
parameter (ADRV9001 provides to user), user parameter (user provides to ADRV9001) and helper parameters (determined by user
which are not needed to provide to ADRV9001 but could be used by the user to derive other required timing parameters).
All the parameters used in Figure 65 are explained further in Table 25. All bounds specified in Table 25 are suggestions for optimal
operation, no hardware or software restrictions prevent a customer from setting values that are out of bounds. The maximum
programmable parameter value is specified in later sections.
Table 25. Receive Timing Parameters Description
Delay
enableSetupDelay
(t )
RxEnaSetup
propagationDelay
(t )
RxPD
enableRiseToAnalogOnDelay
(t )
RxEnaRise2AnaOn
enableRiseToOnDelay
(t )
RxEnaRise2On
enableGuardDelay
(t )
RxGT
enableFallToOffDelay
(t )
RxEnaFall2Off
enableHoldDelay
(t )
RxEnaHold
Design Strategy for Receive Timing Parameters
As described, ADRV9001 provides user enableSetupDelay which is the time required to power up the receiver front end. By knowing that,
user could set the RX_ENABLE pin high at least enableRiseToOnDelay in advance as shown in Figure 64. In regular TDD mode, that is,
no power savings or frequency hopping, enableRiseToAnalogOnDelay should always be set to 0, so that analog power up begins
Provided By Bounds
ADRV9001 Min: N/A
Parameter
Max: N/A
Helper Parameter Min: N/A
Max: N/A
User Parameter Min: 0
Max: duration of
power up tasks in
power savings or
frequency
hopping modes.
User Parameter Min: t
RxEnaRise2AnaOn
Typ: t
RxEnaRise2AnaOn
t
RxEnaSetup
Max: None. Must
be optimized to
be minimal.
User Parameter Min: TBD
Max: TBD
User Parameter Min: 0
Max: None. Must
be optimized to
be minimal.
User Parameter Min: t
RxEnaFall2Off
Max: None. Must
be optimized to
be minimal.
(Recommended
Max: t
RxEnaFall2Off
t Note
RxPD
t is forced
RxEnaFall2Off
to 0 currently.)
Rev. PrC | Page 76 of 338
Preliminary Technical Data
Comments
No PLL tuning @ frame boundary: 8 μs (analog power-up time)
PLL tuning @frame boundary: 758 μs (Analog Power-Up Time + PLL Tuning
Time)
(The PLL tuning time 750 μs refers to the case when internal LO is used. When
external LO is used, users should calculate and use their own PLL tuning time.
Note the time required for PLL tuning is continuously improving in the
future.).
This parameter should be measured by user and it is profile dependent and
board layout dependent. It does not need to provide to ADRV9001, however,
it can be used to derive values for other parameters required by ADRV9001.
Will only be set to non-zero values if using power savings or frequency
hopping. See later sections to determine ho to choose a non-zero value.
If set to t , the actual delay is t
RxEnaRise2AnaOn
+
TBD
Ideally, RX_ENABLE falling edge arrives when the last valid data is received
over the air. By setting this value greater than 0, ADRV9001 can continue
receiving guard symbols, while signaling to certain algorithms or other
systems that the valid data for the frame has already been received.
The interface is disabled only after analog power down has completed.
@ min bound: Some of the data received at the antenna may not make it over
the interface.
@ max bound: Digital datapath and Rx SSI interface remains enabled until last
received data is propagated to the interface.
+
+ t .
RxEnaRise2AnaOn RxEnaSetup