TGSL discrimination

[SasuG]

Hello, I tried to understand how can discriminate in this schematics and i don t understand very well, I have the article that was put on this forum, I studied it but i didn t understand exactly what it works.[COLOR=rgb(33,33,33)] If anybody who can explain me in a few words how can discriminate this detector.
I understand that exist 2 axes A and B which represent synchronous demodulators, but i don t understand how works more exactly the variable scale factor.


I don t know how can i attached a pdf file, but the schematics is for TESORO GOLDEN SABRE LIGHT.
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[homefire]

Go to the Projects Board and down load the Build Document. All is explained. Discrimination is based on Phase Relationship of Rx and Tx.

[Nandor]

Tesoro's discriminate metals by their phase shift. The higher the conductivity the higher the phase shift. Silver is the best non ferrous conductor so it has the highest phase shift compared to the Tx signal, copper and aluminium and gold have less. The detector compares Tx and Rx signals so if a metal passes the coils surface there will some change in the Rx's received signal compared to the Tx's trasnmitted signal. Ferrous metal like pure iron cause amplitude change so the detector knows that it must be iron not silver which causes phase shift so iron will be discriminated. The further you turn the disc potmeter nonferrous metal with less phase shift will be disced out, aluminium-gold stuff-little rings-pull tabs-nickel coins-copper-silver.

[SasuG]

Ok, thanks!

[SasuG]

thank you very much, it was very helpful what you said.

[kt315]

Silver is the best non ferrous conductor

yup. but for Eddy current silver and gold are bad conductor.
you have to learn physics more precisely.
https://en.wikipedia.org/wiki/Eddy_current

[Nandor]

And also watch The Shining!