View Single Post
Old 28th Feb 2012, 9:42 pm   #11
amornummi
Triode
 
Join Date: Mar 2008
Location: Huddersfield, West Yorkshire, UK.
Posts: 45
Default Re: VMARS RA17 product detector modification

Lock in occurs when the IF input signal causes changes in the BFO frequency.
Due to coupling between signals.
Dosen't need much to upset , especially when both signals nearly same freq.
The 6BE6 has perhaps 20 Db isolation , ring mixer has twice this , plus another 10 Db due to extra audio gain.
The audio out is clean sine wave down to 20 c/s.
amornummi is offline