Datasheet

MPY634
8
SBFS017A
www.ti.com
FIGURE 9. Linear AM Modulator.FIGURE 8. Sine-Function Generator.
MPY634
X
1
+V
S
X
2
Out
SF Z
1
Y
1
Z
2
Y
2
–V
S
–15V
+15V
V
OUT
= (10V) sin
Where
= (π/2) (E /10V)
4.7kΩ
Input, E
0 to +10V
With a linearly changing 0-10V input, this circuit’s output follows
0° to 90° of a sine function with a 10V peak output amplitude.
4.3kΩ
3kΩ
10kΩ
18kΩ
θ
θ
θ
θ
FIGURE 11. Balanced Modulator.
Carrier: f
C
= 2MHz, Amplitude = 1Vrms
Signal: f
S
= 120kHz, Amplitude = 10V peak
MPY634
X
1
+V
S
X
2
Out
SF Z
1
Y
1
Z
2
Y
2
–V
S
–15V
+15V
Carrier Input
E
C
sin ω t
The basic muliplier connection performs balanced modulation.
Carrier rejection can be improved by trimming the offset voltage
of the modulation input. Better carrier rejection above 2MHz is
typically achieved by interchanging the X and Y inputs (carrier
applied to the X input).
1kΩ
V
OUT
470kΩ
+15V –15V
Modulation
Input, ±E
M
Carrier
Null
FIGURE 10. Frequency Doubler.
Frequency Doubler
Input Signal: 20Vp-p, 200kHz
Output Signal: 10Vp-p, 400kHz
MPY634
X
1
+V
S
X
2
Out
SF Z
1
Y
1
Z
2
Y
2
–V
S
(A
2
/20) cos (2 ω t)
Squaring a sinusoidal input creates an output frequency of
twice that of the input. The DC output component is
removed b
y
AC-couplin
g
the output.
R
C
A sin ω t
–15V
+15V
MPY634
X
1
+V
S
X
2
Out
SF Z
1
Y
1
Z
2
Y
2
–V
S
–15V
+15V
V
OUT
=
1 ± (E
M
/10V) E
C
sin ωt
Carrier Input
E
C
sin ωt
By injecting the input carrier signal into the output through connection
to the Z
2
input, conventional amplitude modulation is achieved.
Amplification can be achieved by use of the SF pin, or Z attenuator
(at the expense of bandwidth).
Modulation
Input, ±E
M