Table 1: Jumper position and adjustability
Model
J1 and J2
Position
Range
Pulse
Rate
Pulse
Width
Frequency
AT-25
1
80cm-30m
3Hz
120-2400µs
25-34kHz
AT-41
2
30cm-20m
5Hz
80-1600µs
35-46kHz
AT-50
3
25cm-15m
6Hz
60-1200µs
43-56kHz
AT-120
4
15cm-7m
10Hz
40-800µs
100-130kHz
AT-200
5
10cm-3m
25Hz
16-320µs
180-220kHz
AT-225
6
8cm-2.5m
25Hz
16-320µs
200-260kHz
Custom
7
—
—
—
—
Custom
8
—
—
—
—
1 0 0 0
0
2 0 0
4 0 0
6 0 0
8 0 0
3 0 0
0
5 0
1 0 0
1 5 0
2 0 0
2 5 0
Figure 2. Capacitance vs. operating frequency
Operating Frequency (
in kHz
)
Capacitance (
in pF
)
Jumper Position and Adjustability
The currently available AT models with their
corresponding pulse width and frequency adjustability
using the T1 development board are shown on Table 1.
(These values are approximate.)
Custom Application
Rows 7 and 8 on the table above are left open for the
designer. On the T1 development board, insert the new
capacitors at C7 and C15 and/or C8 and C16.
Calculate the capacitance value for C7 and/or C8 to
produce a new minimum pulse width as follows:
C = PW/175, where C is in µF and PW is in µsec.
The maximum pulse width will be approximately 20
times the minimum pulse width. To find the
capacitance value for C15 and/or C16 which will
produce a new operating frequency, refer to Figure 2.
Alternatively, an external pulsed signal (such as one
generated by a microprocessor) may be amplified and
applied to a transducer using the T1 development
board. In this case, disconnect the circuit at R9
(bypassing the signal generation portion of the T1
development board) and connect the external signal to
Q2 and Q3.
AIRMAR
TECHNOLOGY CORPORATION
35 Meadowbrook Drive, Milford, New Hampshire 03055-4613, USA
Phone (603) 673-9570
■
Fax (603) 673-4624
