ENDEVCO 2680
INSTRUCTION MANUAL
IM2680
Page 1-4
6.
OPTIONAL FILTERS
An optional low-pass filter is factory installed in the Charge Amplifier if specified on the Customer
Purchase Order. Optional filters are available in two, four, and six pole low-pass Butterworth
configurations that provide the Charge Amplifier with a specific frequency response. If a Charge
Amplifier contains an optional filter, the model number will contain a three-digit suffix (dash
number) to indicate the
filter's 5% frequency in Hz.
The first two digits are significant numbers
and the third indicates the numbers of zeroes. As an example, the Model 2680M12-101 Charge
Amplifier has two-pole low-pass filter installed with a flat response up to 100 Hz. Table 1-3
provides a list of the various filters by dash number and frequency responses of each.
7.
ACCESSORIES
Accessories for the series of Charge Amplifiers vary according to the type of output connector
installed on the unit. All Charge Amplifiers are shipped with mounting hardware, and those units
with output connectors installed will have a mating connector for connecting input power and
readout devices.
8.
APPLICATION
The Model 2680 Series of Airborne Charge Amplifiers are ideally suited for inflight telemetry
applications and other dynamic instrumentation systems using Transducers such as Piezoelectric
Accelerometers, Microphones, Force Gages or Pressure Pickups. The small size, light weight,
low-power consumption, and the use of long cables to connect Transducers to the Charge
Amplifier, enables the unit to be used in ground and laboratory testing, rocket test stands,
combined environmental testing, steam turbines and other industrial applications.
____________________________________________________________________________
Model Low Frequency
High Frequency
2-Pole Filter
4-Pole Filter
6-Pole Filter
Dash -
10%/+5% Rolloff
±5% Flat Response
-3 dB Typ. -12 dB Typ. -3 dB Typ. -40 dB Min. -3 dB Typ. -40 dB Min.
No.*
(Hz)
(Hz)
(Hz)
(Hz)
(Hz)
(Hz)
(Hz)
(Hz)____
None
3 to 5
5 to 20 000
-101
3 to 5
5 to
100
200
400
150
480
140
325
-201
3 to 5
5 to
200
400
800
300
960
280
650
-501
3 to 5
5
to
500
1 000
2 000
750
2 400
700
1 625
-102
3 to 5
5
to 1 000
2 000
4 000
1 500
4 800
1 400
3 250
-202
3 to 5
5 to 2 000
4 000
8 000
3 000
9 600
2 800
6 500
-502
3 to 5
5
to 5 000
10 000
20 000
7 500
24 000
7 000
16 250
-103
3 to 5
5
to 10 000
20 000
40 000
15 000
48 000
14 000
32 500
-203
3 to 5
5 to 20 000
40 000
80 000
30 000
96 000
28 000
65 000
______________________________________________________________________________________________________
* Add dash number to Model Number. For example: 2680M12-101 has a 2-pole, low-pass filter which is flat up to 100 Hz.
Specify number of poles of filter, if other than 2.
______________________________________________________________________________________________________
TABLE 1-3: LOW-PASS FILTER FREQUENCY RESPONSE VERSUS MODEL DASH NUMBER
