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

Where

= (

π/2) (E /10V)

4.7k

Ω

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.

4.3k

Ω

3k

Ω

10k

Ω

18k

Ω

θ

θ

θ

θ

FIGURE 11. Balanced Modulator.

Carrier: f

Signal: f

MPY634

X

1

+V

S

X

2

Out

SF

Z

1

Y

1

Z

2

Y

2

–V

S

–15V

+15V

Carrier Input

E

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).

1k

Ω

V

OUT

470k

Ω

+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

ω t)

Squaring a sinusoidal input creates an output frequency of

twice that of the input. The DC output component is

removed by AC-coupling 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

1 ± (E

Carrier Input

E

By injecting the input carrier signal into the output through connection

to the Z

Amplification can be achieved by use of the SF pin, or Z attenuator

(at the expense of bandwidth).

Modulation

Input, ±E

M