LA1193M, 1193V

No.4715-11/22

3D-AGC Sensitivity,

∆f and V20 Characteristics

AGC sensitivity

W-AGC sensitivity

N-AGC sensitivity

Desired station

AGC sensitivity

V20 (desired station

field strength)

Two signal sensitivity

suppression improvement

∆F

Figure 3

3D-AGC Sensitivity,

∆f and V20 Characteristics

— The W-AGC sensitivity is determined by the antenna RF circuit selectivity independently of V20.

— The N-AGC sensitivity is determined by the antenna, RF and mixer circuit total selectivity when V20 is 0.6V or

greater. It is determined by that selectivity and V20 when V20 is over 0.6V.

— The improvement in two-signal sensitivity suppression is the shaded area in the total AGC sensitivity and

corresponds to the section occupied by the N-AGC.

4. Mixer

The mixer circuit used in this IC is a balanced input/balanced output double balance mixer circuit.

• Input Format

Emitter input

Input impedance : 25

Ω

Optimization of the component geometry, emitter

current and bias allow this circuit to achieve the

following performance.

Mixer input usable sensitivity : 15dB

µ

Mixer input IMQS* : 90.5dB

µ

Note : *Mixer input IMQS is defined as follows :

fr = 98.8MHz, no input

fu1 = 98.8MHz, 1kHz, 30% modulation

fu2 = 99.6MHz, no modulation

IMQS is the interference 1 and 2 input levels such that when an

interference signal with the same level is input to the mixer and

distortion occurs at the mixer, the generated IM output has a S/N

ratio of 30dB.

OSC

MIX

Figure 4

Mixer Circuit

(Improved by 6.0dB

µ over previous products.)