Negative Group Delay Circuit

| > OMG! Current leads voltage in a capacitor! Who'd a thunk it? | > Fig 7 shows a square wave input, but fig 8 is not square and | > therefore not the input as claimed. Fig. 6 has two resistors both | > labelled R1 and two capacitors both labelled C1, those guys | > must have had too much saki. | >

| >

| | I think you've missed the point, which is not the phase | relationship of E and I in a capacitor. | Figure 8 shows the input to the _negative delay circuit_.

There is no such animal as a "negative delay", and Fig 8 shows the trace on an oscilloscope, NOT any "input".

| What's wrong with having 2 R1's & 2 C1's to show that they | have identical values in that paper?

For the very obvious reason that the output drives the voltage at at the junction of C1 and R1 and now you have no idea which junction I'm referring to, that's what wrong. What's wrong with calling "LED in" and "LED out" just "LED" to show they have identical colours in Fig 7, and why are LED and LED not shown connected to R1 and C1 in Fig 6?

No problem.

1. Publish "research" linking negative group delay to global warming.

1. Mysterious money suddenly pouring in.

2. Use up money to create paper proving beyond doubt that climate change is linked to CO2 through negative group delays.

1. Rinse and repeat. Rinse and repeat. etc.

What they're holding back is that the circuit is dependant on using devices where the substrates have been doped with recently developed componds incorporating thio-timoliine-

H.

Linear phase digital filters routinely deal with negative time. All that is needed is enough total delay in the sampling process to allow casuality.

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Figure 8 shows the traces labeled "output" and "input". Did you miss that? Or are you objecting to the ellipsis?

See figure 7. Do you see the words "Negative delay circuit"? Figure 8 shows the input and the output pulses of that circuit. You have to read with some understanding. The filters will make the square wave pulses look like the waveforms in the figure.

Well, with you talking and exhibiting zero understanding, you're right. I have no idea what _you_ have in mind.

If you wanted to be clear you could've used one of these: The voltage at junction of R1 and R1. The voltage at the non-inverting input to the op amp.

However, the paper is not intended to be a tutorial on Bessel filters. There is no need to study the filter at all. All you need to know is the input and output wave shapes.

Apparently the names they used carry no meaning for you. They identify the input and output sides of the "Negative delay circuit".

You don't know electronics? Or you didn't read it carefully? Or you're a troll?

Figure 6 is labeled "2nd-order Bessel low pass filter" The LEDs are not connected to it.

The LEDs are show directly connected at the input and the output of the "Negative delay circuit". There is a cable (or wire) connection from the output of the filter section to the input of the delay section.

There is *no* connection of any LED to "R1 and C1 in Fig 6"

I'm sorry, but I have the impression that you either don't know enough electronics to understand where your point of view is amiss, or that you aren't properly reading the sections of the paper that you refer to, or that you're just trolling.

Ed

Negative group delay can be implemented by, for instance, passing a 1 ms pulse (group centered at 0.5 ms) to a nonretriggerable 1 us one-shot (group at 0.0005 ms). Sure enough, the group center of the one-shot is earlier than that of the original pulse.

But, it's not the same as 'an output before there is an input'. No time travel, no sublimated thiotimoline required.