10. Application Circuit using the IF count method

The LA1136N and LA1137N can be configured for tuning using either the stop detector or the IF count method. The application

circuits are examples of tuners using the IF count method. The stop detector can be used in any of the application circuits by

making the circuit modifications shown below.

11. Improving Fidelity

Distortion for low-frequency(fm

% 100 Hz), high-modulation signals can be reduced by increasing the capacitance connected to

AGC response time to an unacceptable level.

12. Loop Antenna Specifications

The recommended loop antennae for the LA1136N and LA1137N are the Korin 42579719100 (LA-1500) and 4257976000

(LA-100A). Note that these are the same antennae previously recommended for the LA1135.

13. AGC ON Level Frequency Characteristics

The frequency at which the sensitivity decreases by –3 dB from the point whenf=1 MHz is as shown below.

Normal

Wideband

LA1136N, LA1137N

37 MHz

24 MHz

LA1135

20 MHz

7 MHz

In other words, in AGC for the main signal, the point at which the AGC sensitivity drops 3 dB is 37 MHz, as shown in the

diagram below. The AGC ON level –3 dB frequencies for narrowband and wideband AGC have been extended from those of the

LA1135 to cover the entire SW3 shortwave band. As a result, the wideband AGC sensitivity is significantly increased and

susceptibility to shortwave interference, reduced. This has been achieved without any increase in dispersion or distortion.

The other pins are the same as those shown in the application circuits.

Ω

AGC ON level variation

± 1dBupto30MHz

LA1136 RF AGC ON mixer input frequency – Hz

Narrowband AGC ON level

fr = 1 MHz

Pin 3 input – dBµ

Wideband AGC ON level

Unit (resistance:

Ω, capacitance: F)

LA1136N, 1136NM, 1137N, 1137NM

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