Datasheet

30129710
FIGURE 15. Beamformer Output with Example 1A Parameters
Example 1B (Code Excitation with Pulse Width Adjust)
Example 1B is similar to example 1A, except that the Pulse Width Adjust feature is enabled for each Channel. Channels 0 to 7 of
the beamformer is programmed such that each P output fires 1/2/3/4/5/6/7/0 fine phase(s) later than the N output and its pulse
width is smaller than the N output by 2/4/6/8/10/12/14/0 fine delays, individually. All of the control steps are similar to example 1A
except for Step 2.
STEP 2.
Write the delay profile as well as Pulse Width Adjust information to each Channel. Here the Channel to Channel delay is the same
as in example 1A; however, the Pulse Width Adjust feature for all of the channels are enabled. The P outputs and N outputs are
never overlapped. See Figure 16.
CD = Coarse Delay, FD = Fine Delay, ND = No Delay.
Channel Register Data Programmed
Fire Delay
Actual Fire
Delay*
P to N Delay & P's Pulse Width
Ch 0 Reg. 00h 10 001 00000000000000 000 b ND
P: 1FD P fires 1FD later than N. P's
pulse width is smaller than N by
2FDs.
N: ND
Ch 1 Reg. 01h 10 011 00000000000010 001 b 2CD + 1FD
P: 2CD + 3FD P fires 2FDs later than N. P's
pulse width is smaller than N by
4FDs.
N: 2CD + 1FD
Ch 2 Reg. 02h 10 101 00000000000100 010 b 4CD + 2FD
P: 4CD + 5FD P fires 3FDs later than N. P's
pulse width is smaller than N by
6FDs.
N: 4CD + 2FD
Ch 3 Reg. 03h 10 111 00000000000110 011 b 6CD + 3FD
P: 6CD + 7FD P fires 4FDs later than N. P's
pulse width is smaller than N by
8FDs.
N: 6CD + 3FD
Ch 4 Reg. 04h 10 001 00000000001000 100 b 8CD + 4FD
P: 9CD + 1FD P fires 5FDs later than N. P's
pulse width is smaller than N by
10FDs.
N: 8CD + 4FD
Ch 5 Reg. 05h 10 011 00000000001010 101 b 10CD + 5FD
P: 11CD + 3FD P fires 6FDs later than N. P's
pulse width is smaller than N by
12FDs.
N: 10CD + 3FD
www.national.com 24
LM96570