N123-134 EXCITER/DEMODULATOR SCHEMATIC
CIRCUITRY
LEAD
LAG
-E
-E
-E
-E
-E
-E
-E
-E
-V
-E
-E
-E
-E
-E
-E REG
+E
+E
+E
+E
+E
+E
+E
+E
+E
+E
+E
+E
+E
+E
+V
+E
+E
+E
+E
+E REG
COMM
COM
8
7
9
6
C2
10
µ
F
25V
C1
10
µ
F
25V
TP7
U2D
10
11
13
3
12
-
+
LM339AN
R31
20K
2
1
R33
20K
D6
1N4148
1N4148
D7
2
3
8
4
1
U4A
-
+
R32
20K
TL082
R30
20K
R34
10K
R35
1K
C11
1
µ
F,63V
11
10
R36
1M
R38
10K
R37
100K
5
6
8
4
7
TL082
VIN
C13
0.047
µ
F
100V
C15
10
µ
F
25V
+
-
U4B
1
8
5
2
9 1314
U5
SMP10FY
7
11
12
10
C12
0.047uF,100V
C14
10
µ
F,25V
C16
0.1
µ
F,100V
R39
10K
C17
NF
C18
100pF
2
3
4
U6
7
6
CA3193
R44
49.9
20K
R45
TP12 (TEST POINT)
12
R40
2.49K
100K
R42
R41
2.49K
R43
100K
CW
C3
0.01
µ
F
C4
0.0022
µ
F
R1
10K
R2
10K
6
11
8
10
5
1
U1
4
12
9
3
2
8038
R9
49.9K
4
5
3
U2A
-
+
12
2 1 R10
12.1K
R11
10K
R12
12.1K
R13
4.99M
7
6 U2B
+
-
3
1
12
LM339AN
R14
100K
C5
220pF
R15
20K
R16
49.9K
R17
1M
12
9
8
3
14
LM339AN
+
-
U2C
R18
1.5K
R19
1.5K
R21
22.1K
R20
100K
CW
C8
1
µ
F,63V
R23
49.9K
0.01
µ
F
C6
C7
33pF
3
2
4
7
6
8
1
+
-
LM301AN
R22
49.9K
U3
1
2
3
Q1
TIP29C
R25
10
D1
1N4148
R24
100K
C9
15pF
D2
D3
1N4148
1N4148
R26
10
C10
0.33
µ
F,63V
Q2
3
2
1
TIP30C
R29
49.9
R27
10K
D4
1N4148
D5
1N4148
R28
464
Q3
2N2222A
2
1
3
TP3
3
4
-
+
R3
10K
R6
10K
R7
10K
R4
18.2K
R5
10K
R8
10K
SAMPLE
CW
CW
CW
CW
DEMODULATOR
OUTPUT SIGNAL
EXCITER
LOAD
11:1 GAIN RATIO
DIFFERENTIAL
INPUT
COMMON
+V UNREG
-V UNREG
COM
WAVEFORM
GENERATOR
SPARE
6
5
OSCILLATOR
FREQUENCY
DEMODULATOR PHASE
OSCILLATOR
AMPLITUDE
DEMODULATOR ZERO
DEMODULATOR SPAN
DIFFERENTIAL AMP
CW
A precision waveform generator
(U1) provides square, triangular and
sinusoidal signals.The frequency of
these signals is controlled by R3, R4,
C3 and C4. U3 controls the amplitude
of the sine wave between 2 and 11
volts peak to peak depending upon
the setting of potentiometer R20.
Transistors Q1 and Q2 provide
output power drive capability.The
load to be excited is connected
between terminals 3 and 4.
The demodulator consists
of a differential amplifier (U4A), an
adjustable span potentiometer (R34),
and a sample and hold integrated
circuit (U5).The sampling pulse for
U5 is generated when the voltage
of the triangular wave rises above an
adjustable reference voltage (R11).
Potentiometer R11 adjusts the phase
of the sampling pulse over a 150˚
range of the signal to be demodulated.
This allows triggering of the sample
and hold circuit at the peak amplitude.
Inverting amplifier U6 provides zero
adjustment of the sampled signal.
The demodulated signal is available at
terminal 12.
Diodes D6 and D7 provide OP
AMP protection against excessive
voltage differential between the input
terminals.
ADJUSTMENTS
FREQ (R3) – provides trimming
capability for exciter frequency
AMPL (R20) – trims excitation
amplitude
PHASE (R11) – adjusts timing of
trigger pulse for peak sampling of
signal to be demodulated
SPAN (R34) – provides approximately
11:1 gain adjustment of the signal
to be demodulated
ZERO (R43) – provides a zero
adjustment of the signal to be
demodulated
NOTES:
1.
■
= PIN 1 (SQUARE PIN)
2.
= INDICATES COMPONENT STANDOFF
3. CW = CLOCKWISE
4. NF = NOT FURNISHED
5.
= +E & +V JUMPERED FOR POWER DISTRIBUTION
(CUSTOMER OPTION)
6. NOTE: Q1 & Q2 PROVIDE OUTPUT POWER DRIVE
CAPABILITY AND ARE POWERED BY ±V UNREG
SECTION OF SUPPLY.
The products described herein are subject to change at any time without notice, including, but not limited to, product features, specifications, and designs.
