ALC (automatic level control) - RF Cafe Forums

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sma100
Post subject: ALC (automatic level control)
Unread postPosted: Tue Mar 16, 2004 1:28 am
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Joined: Tue Mar 16, 2004 1:26 am
Posts: 1
Hello,

Anybody know how I can design an ALC circuit with a pin attenuator and a crystal detector. Freq range (DC - 500 MHz).

Thanks.

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Doug
Post subject: ALC
Unread postPosted: Tue Apr 20, 2004 3:40 pm

Coupling off the output, convert to dc with the crystal detector and varyig the PIN diode with the dc at the input. :|

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Kirt Blattenberger
Post subject:
Unread postPosted: Tue Apr 20, 2004 9:15 pm
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Site Admin
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Joined: Sun Aug 03, 2003 2:02 pm
Posts: 308
Location: Erie, PA
Greetings SMA100:

* Here's a really good App Note on how to build a PIN atteunator from Alpha Industries (now Skyworks).

...and another from General Microwave (now Herley).

* Here's an App Note from Agilent for a detector.

...and another from the Electronic Warfare Handbook site.

These and others can be found on the App Notes page right here on RF Cafe.

Good luck to you.

- Kirt B. :mrgreen:

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Puck
Post subject:
Unread postPosted: Wed May 05, 2004 3:30 pm

Think about the time response and you will get it. With properly made ALC you can get 6dB or more s/n ratio for voice. Video is different. Generally it provides dynamic range compression.

Posted 11/12/2012