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CXA3179N

Application Notes

1) Power Supply

The CXA3179N, with built-in regulator, is designed to permit stable operation at a wide range of supply

2) Oscillator Input

Oscillator input method

a) Using Pins 1 and 2, input a 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 24 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) Wiring to the IF limiter amplifier input (Pin 5) should be as short as possible.

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

connected to QUAD should be as short as possible to reduce the interference with the mixer output and

IF limiter amplifier input.

1

2

3

Ceramic

filter

1

2

3

From

local signal

Ceramic

filter

Fig. 1

3

4

5

6

7

8

9

Wire as short and apart as possible

As short as possible

Fig. 2