Brute Force Sweep - Analog Devices AFDF7021 Application Note

Application Note

BRUTE FORCE SWEEP

Figure 6 outlines a suggested method for sweeping all I and Q,
gain and phase values. The resulting array contains 31 × 31 =
961 RSSI values. The minimum value represents the optimum
settings.
Note that if gain mode is used, instead of attenuate mode, the
resulting array will be 63 × 31 = 1953 RSSI values. However, in
START
SET IR_GAIN_ADJUST_UP/DN = ATTENUATE (DECIMAL 1)
SET IR_GAIN_ADJUST_I/Q = Q CHANNEL (DECIMAL 1)
SET IR_GAIN_ADJUST_MAG = (DECIMAL 15)
SET IR_PHASE_ADJUST_DIRECTION = Q CHANNEL (DECIMAL 1)
SET IR_PHASE_ADJUST_MAG = (DECIMAL 15)
RECORD RSSI
DECREMENT GAIN,
RECORD RSSI
GAIN = 0?
YES
SET IR_GAIN_ADJUST_I/Q = I CHANNEL (DECIMAL 0)
INCREMENT GAIN
RECORD RSSI
GAIN = 15?
YES
PHASE SET
NO
TO Q CHANNEL?
PHASE = 15?
YES
SET IR_PHASE_ADJUST_DIRECTION
= I CHANNEL (DECIMAL 0)
END
Figure 6. Brute Force Procedure
this mode, the results wrap around and there will be two
identical minimums on the 2D surface. Thus, there is no benefit
in using gain mode.
Figure 7 shows an example array of results obtained using the
IR_Sweep_Cal software, available from Analog Devices, Inc.,
installed with the evaluation software.
NO
NO
YES
INCREMENT PHASE
NO
SET IR_GAIN_ADJUST_I/Q =
PHASE = 0?
Q CHANNEL (DECIMAL 0)
RECORD RSSI
YES
Rev. 0 | Page 7 of 12
AN-1258