LA1136N, LA1137N Usage Notes

1.

Do not connect the antenna alignment circuit and local oscillation circuit.

2.

The coils should be specified to obtain an output level of –25 dBm (43.6 mVrms) for the given input levels shown below,

Antenna input

20.0 dBµ (Note)

Mixer input

30.5 dBµ

IF input

38.0 dBµ

Detector input

106.0 dBµ

Input connections

Note : The antenna input can be adjusted by changing the number of turns in the primary winding of the alignment coil in

accordance with the AGC figure-of-merit.

3. Coil Design Notes

(1) RF alignment coil

.

Gain adjustment: The gain is adjusted by varying the primary turns ratio of the primary coil.

.

Coupling: The design of this coil is geared towards critical coupling.

The coupling is dependent on the turns ratio of the primary coil and the secondary coil:

Tight coupling: High turns ratio

Loose coupling: Low turns ratio

.

With tight coupling, the selectivity characteristic develops a double hump; when making a tracking adjustment, it must

be noted that misadjustment can occur, leading to a deterioration of the dual signal characteristics.

.

With loose coupling, selectivity increases, but the sensitivity error within the band of the RF alignment itself also

increases.

During design, be certain to confirm data such as that for coil specifications. Furthermore, it is also necessary to note that

although the turns ratio of the primary and secondary coils have the greatest bearing on coupling, the shape of the coil core

and the manner in which the coil is wound also have an impact.

Mixer input

Antenna input

Detector input

IF input

V12 = 0 for LA1136N

Unit (resistance:

Ω, capacitance: F)

LA1136N, 1136NM, 1137N, 1137NM

No. 3507-12/28