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CXA1999N

Application Note

1) Power Supply

The CXA1999N, with built-in regulator, is designed to permit stable operation at wide range of supply

2) Oscillator Input

Oscillator input method

a) Using Pins 1 and 2, input self-excited oscillation signal through the composition of a Colpitts type crystal

oscillator circuit.

b) Directly input a local oscillation signal to Pin 1.

3) Mixer

The mixer is of double-balance type. Pin 20 is the input pin. Input though a suitable matching circuit. The

input impedance is 2.0 k

Ω.

Pin 3 serves as the output pin for the mixer, and a load resistance of 1.5 k

Ω is incorporated.

4) IF Filter

The filter to be connected between this mixer output and the IF limiter amplifier input should have the

following specifications.

I/O impedance : 1.5 k

Ω ±10 %

Band width

: Changes according to applications.

5) IF Limiter Amplifier

The gain of this IF limiter amplifier is approximately 100 dB. Take notice of the following points in making

connection to the IF limiter amplifier input pin (Pin 5).

a) Be sure to wire to the IF limiter amplifier input (Pin 5) is as short as possible.

b) As the IF limiter amplifier output appears at QUAD (Pin 8), be sure to wire to the ceramic discriminator

connected to QUAD is as short as possible and reduce the interference with the mixer output and IF

limiter amplifier input.

2

3

1

Ceramic

filter

1

2

3

From local signal

Ceramic

filter

Fig. 1

4

5

6

7

9

3

8

Shortest possible wirings which

must be apart as far as possible

As short as possible

Fig. 2