Thanks Lawrence: I am starting to understand its operation now.
By making the mixer regenerative, it enables a sharp increase in the selectivity of the mixer's tuned grid cct. At the same time, it also acts as a conventional freq. changer by virtue of the separate local oscillator, the tuning of which is ganged to the tuning of the mixer grid cct. to produce a constant freq. for the I.F. The (second) detector is also regenerative by virtue of the inductance in its cathode, the Q of that inductance being variable by the variable resistance across it. Thus the degree and threshold of the regenerative action is controllable; the bias for that detector being obtained by auto-bias: the 1 k-ohm resistor in the cathode, suitably by-passed to R.F. by a capacitor.
Anyway, that's my 'first-off' analysis: can you fault it ? If so, then please do so.
; I'm always prepared to learn 
Going off on a related tangent, I wonder if the Mr. Jones (as in this cct.) is the same Mr. Jones whose name is associated with the Jones noise-balancing cct., a derivation of which features in the Collins 136-series of 'noise blankers', intended to be fitted into receivers like the 75A4, 75S1 and the KWM-1 ?
Al.
By making the mixer regenerative, it enables a sharp increase in the selectivity of the mixer's tuned grid cct. At the same time, it also acts as a conventional freq. changer by virtue of the separate local oscillator, the tuning of which is ganged to the tuning of the mixer grid cct. to produce a constant freq. for the I.F. The (second) detector is also regenerative by virtue of the inductance in its cathode, the Q of that inductance being variable by the variable resistance across it. Thus the degree and threshold of the regenerative action is controllable; the bias for that detector being obtained by auto-bias: the 1 k-ohm resistor in the cathode, suitably by-passed to R.F. by a capacitor.
Anyway, that's my 'first-off' analysis: can you fault it ? If so, then please do so.
; I'm always prepared to learn Going off on a related tangent, I wonder if the Mr. Jones (as in this cct.) is the same Mr. Jones whose name is associated with the Jones noise-balancing cct., a derivation of which features in the Collins 136-series of 'noise blankers', intended to be fitted into receivers like the 75A4, 75S1 and the KWM-1 ?
Al.
