AB1600_V0.3
4.3
Crystal Trim
When a 16MHz crystal is used on the DUT, user may adjust cap value to fine tune the output
tuned
cap value into EEPROM. Whenever DUT is powered on, the parameters in EEPROM will be read out and
write into DUT, thus the output 16MHz reference clock frequency could be set to the trimmed value.
The crystal trimming can be performed either by a spectrum analyzer or a frequency counter. The
method is described below,
Figure 4-9
Crystal Trim function
When a spectrum analyzer is used:
-
-tone RF signal at 2441MHz. Using spectrum
analyzer to measure the frequency of the tone at RF output port, and then fine-tune the cap
value until the carrier frequency offset is less than (2.4 G * n ppm) Hz. (n ppm is the reference
clock accuracy spec of the Bluetooth specifications)
When a frequency counter is used:
-
Measure the clock with a frequency counter, and then fine-tune the cap value until the
reference clock frequency offset is less than (16 M * n PPM) Hz. (n ppm is the reference clock
accuracy spec of the Bluetooth specifications)
Summary of Contents for AB1602
Page 5: ...AB1600_V0 3 Figure 2 2 Figure 2 3 1 2 3 4 5 6 3 3V GND RTS CTS TX RX...
Page 7: ...AB1600_V0 3 Figure 2 5...
Page 11: ...AB1600_V0 3 Figure 4 2 Continuous data transmission setting of Tx Tab...
Page 13: ...AB1600_V0 3 Figure 4 4 LE Transmitter Test setting of Tx Tab...
