TSH512 datasheet(22/31 Pages) STMICROELECTRONICS

Part #	TSH512

Description	Hi-fi stereo/mono infrared transmitter and stereo sub-carrier generator

PDF	31 Pages

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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22 / 31 page

General description

TSH512

22/31

Doc ID 8120 Rev 7

Figure 29.

VOX delay and sensitivity schematics

On pin 6, Rpeak and Cpeak integrate the rectified audio signal with a short time constant. This

filtered signal follows the audio amplitude.

Figure 30.

VOX integrator and monostable schematics

The self-adaptive VOX threshold is necessary because the ambient background noise

variation is slow compared to the voice or the music. On pin 28, RCOMP and CCOMP

integrate the amplitude to follow the background amplitude. Therefore, the comparator

switches when an audio signal appears over the background noise. Referring to Figure 2,

CCOMP will be typically a 100 nF capacitor and RCOMP will be determined depending on the

audio signal.

As soon as an audio signal is detected, the output of the monostable switches to "high" state

and enables both output buffers. The monostable output is pin 27 and is called VOX-MUTE.

TSH512 Datasheet(PDF) 22 Page - STMicroelectronics