Figure 8.9 A Quadrature detector. The circuit begins on the left with the usual I F tube with only the plate connected to the primary of the transformer. The bottom end of the secondary goes to ground. The top goes to the control grid of the detector tube. The cathode of this same tube goes through the parallel combination of R1 and C2 to ground. The screen grid goes through R3 to B plus. The screen also goes through C3 to ground. Grid number 3 of the tube, known as the quadrature grid, connects to the top of a parallel inductor and capacitor. The other end of both goes to ground. The plate goes through R2 to B plus. The plate also goes through C1 to ground. The plate also goes through C4 to the audio output. End verbal description.
go back.