> If there is a clear benefit, and it's known to those skilled in the art, it shouldn't be hard to find examples of it in use.
Sometimes the actual benefits must wait on another development. 10,000BC Ooog invents an axle brake. It has no application. Ooog slips the examiner 2 clams and gets a patent-rock anyway. No royalties. 9,990BC, Mok invents and patents the wheel, rolls downhill and dies. His heirs now license Ooog's suddenly useful brake.
Or.... the solid-state FET was proposed by Shockley, who was anticipated (by decades) by Lilienfeld. But practical useful FETs had to wait for improved processing. Leakage in a BJT is swamped by base current. A leaky FET ain't much better than a BJT. Epitaxial and oxide improvements made high-quality FETs (especially MOSFETs) practical more than a decade after Shockley's FET proposal. There are very few in-use FET examples from the 1950s, even into the 1960s. But should Shockely or Lilienfield have been denied patent positions on FETs and FET circuits just because they could not buy one at Lafayette? (I dunno.)
> Not identical... (better?).
The Wai et al patent uses two polarities of JFET, you only have one. Distinctions have been sliced far thinner than this.
The Wai et al patent is SE in SE out. Yours is differential input (albeit one input grounded), derives a differential signal, then mixes to SE in an additional stage.
The Wai et al patent uses a lot of R-C networks, many more than the similar part of your plan. I'm not inclined to wade through a dozen pages wondering what good they are. If they have any benefit, your plan lacks said benefit.
I have not read all the tedious "I Claim"s. And I have not found even approximate component values(?). But low noise and battery economy are mentioned. If a good operating current is 4mA, the Wai plan can run 2mA in each of two devices in series across the battery, get 4mA performance with 2mA battery consumption. Yours may actually need >8mA supply current to approach the noise of one 4mA device. Not that you Claim low power, or that phono pickup preamp noise matters (unless excessive).
If _I_ were the King's Patent Examiner, I'd throw 7183842 back for a clear narrow specific application benefit. Naturally Wai et al want the broadest possible interpretation.
As a technology user in the field, I'd say Wai et al have not usefully Disclosed anything novel (not even the series-connection, see Different Differential on this forum). Disclosure is part of the social contract used to excuse the granting of monopolies. But that social contract is reading pretty faint these days.
