6.

Wideband AGC Sensitivity

The wideband AGC circuit two-signal sensitivity and shortwave interference suppression characteristics have been achieved by

sensitivity can be increased by increasing the external sensitivity adjustment resistor (30

Ω). However, the voltage drop across this

resistor can cause the cascade AGC transistor to saturate. Therefore, if the sensitivity is to be increased by a large amount, a choke

coil should be added as shown in the figure below.

7.

The local oscillation level increased during LW (approx. 50°C or greater)

27 k

Ω should be added between pins 19 and 23 for LA1136N, and between pins 15 and 19 for LA1137N. Not necessary for MW.

8.

Image Interference Reduction

Image interference in the alignment circuit can be reduced by up to 70 dB at fr = 1.4 MHz by injecting a 2.3 MHz trap signal into

the primary coil. Note that this technique reduces the sensitivities at frequencies above 1.4 MHz.

9.

Upgraded Features of LA1136 and LA1137 to LA1136N and LA1137N

Upgraded features

LA1136, LA1137 LA1136N, LA1137N

IF count buffer output voltage

74 dBµ, zero modulation,

fr = 1 MHz when STOP RQ=0V

Test circuit LA1137N

80 mVp-p

1.5 mVp-p

Signal detector output voltage

Test circuit LA1137N

0.7 V

5 V

Unit (resistance:

Ω, capacitance: F)

Unit (resistance:

Ω, capacitance: F)

LA1136N, 1136NM, 1137N, 1137NM

No. 3507-16/28