Message	Date	From	Subject
3003	2009-05-10 17:42:26	Kenneth Stringham	Purifying Mixers
Amin, This is true, but in my experience you will attenuate the higher order products more than the desired signal. For example: If you add a 3dB attenuator, you will 20log(Ratio) attenuation which at 2F you will get 6dB attenuation and at 3F you will get you 9dB. As you can see this will increase by 3dB for each order higher. If you decrease the signal by 10dB the 2nd order product will decrease by 16dB and the 3rd order product would decrease by 19dB. BTW, 50 ohm terminations are only true when dealing with a ring type balanced mixers. Active type mixers will have different termination requirements. Ken - AE1X
3005	2009-05-10 19:56:26	gt25psi2002	Re: Purifying Mixers
Dear Ken, Thanks very much. I learnt a simple but precious knowledge today. Best regards, Amin

Amin,

This is true, but in my experience you will attenuate the higher order products more than the desired signal. For example: If you add a 3dB attenuator, you will 20log(Ratio) attenuation which at 2F you will get 6dB attenuation and at 3F you will get you 9dB. As you can see this will increase by 3dB for each order higher. If you decrease the signal by 10dB the 2nd order product will decrease by 16dB and the 3rd order product would decrease by 19dB.

BTW, 50 ohm terminations are only true when dealing with a ring type balanced mixers. Active type mixers will have different termination requirements.

Ken - AE1X