TA2057N Ver la hoja de datos (PDF) - Toshiba

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Fabricante

TA2057N

TOSHIBA Bipolar Linear Integrated Circuit Silicon Monolithic

Toshiba 

Application Note

1. How to control the IF count output signal (pin(9) output)

V9

V9

TA2057N

H

Open

H

Open

Tun LED

On

Off

Come on

Non output

Non output

Non output

Mute Circuit

On

Off

· Whether or not there is the IF count output signal (pin(9) output) is determined by the and of the pin(9) control

voltage: V9 and tuning LED on / off switching.

In the condition of

V9: High (active high, VTH = 2V (type.) )

Tun LED: On (Vin ≥ VL + 2dB (type.) )

The IF count output signal come out from the pin(9).

· The signal waveform is FM: Rectangular, AM: Differential wave, and the level is 500mVp-p (typ.)

· Mute circuit is action by the pin(9) control voltage: V9 (at high) in matrix output circuit.

2. How to adjust the IF count output sensitivity

· The IF count output sensitivity (search sensitivity) can be adjusted by varying the IF amp. Gain for FM and

varying the mixer gain for AM.

· However, this is only possible at the auto-tuning mode (external voltage supplied to pin(9) is at high level). The

original gain returns while receiving a broadcast station (supplied voltage to pin(9) is at low level).

8

2002-10-30

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