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Typical Measurement
9
SNAU217A – August 2017 – Revised November 2017
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Copyright © 2017, Texas Instruments Incorporated
LMX2572EVM Evaluation Instructions
3.2.3
Automatic Ramping
This ramping mode supports wider ramp frequency, however there are glitches in the middle of the ramp
because of VCO calibrations which are required so as to ensure the continuity of the ramp.
Table 4. Automatic Ramp Example
PARAMETER
EXAMPLE VALUE
Ramping start frequency
4740 MHz
Ramping stop frequency
4860 MHz
Phase detector frequency
50 MHz
Ramp up / down time
1000 µs
RAMP_LIMIT_HIGH
5060 MHz
RAMP_LIMIT_LOW
4540 MHz
f
OSCin
100 MHz
CAL_CLK_DIV
0
RAMP_THRESH
40 MHz
Pause time for VCO calibration
500 µs
Figure 11. Automatic Ramp Setting
Figure 12. Automatic Ramp
