LA1193M, 1193V

No.4715-8/22

Continued from preceding page.

Pin No.

Function

Equivalent circuit

Note

17

IF, AGC, VCC

20

Keyed AGC input

Controls the narrow AGC.

1. Oscillator Circuit

Steps were taken to prevent AMR degradation during earlier product type

AGC operation, since the local oscillator block in this IC has independent

Vd (pin 5) and ground (pin 3) connections.

This is a Colpitts oscillator and has the same structure as that used in

earlier circuits. The oscillation level and intensity are changed by

capacitors C2-4, C4 and CP.

2. Local Oscillator Buffer Output

This buffer is an emitter follower circuit.

If desired, the buffer efficiency can be increased by inserting a resistor

between pin 1 and ground to pass more current through the buffer

transistor. However, this current must be limited so that Pdmax for the

package is not exceeded.