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Can passive phase shifters be implemented without a variable delay element?

On Jan 15, 2018, snipped-for-privacy@notreal.com wrote (in article):

One can certainly use the above methods, and they are widely used in radar, at least for sine waves. However, typical pulsed radar waveforms are far wider band than a sine wave. The various filter methods are wideband enough for many applications, but not high (range) precision radars.

I?ve also used a 90-degree hybrid, two attenuators, and a summing junction to implement a variable phase. The hybrid is based on filters. I?ll have to model this and see how the group delay varies with phase.

Joe Gwinn

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Joseph Gwinn
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On Jan 16, 2018, George Herold wrote (in article):

Transient response. There is a key question, a question equivalent to the issue of distortion of wideband signals. Pulse radar waveforms are transients. This too should be modeled.

Joe Gwinn

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Joseph Gwinn

On Jan 15, 2018, snipped-for-privacy@gmail.com wrote (in article):

It?s the waveforms that are wideband, to achieve very high slant range resolution. As a practical matter, it?s difficult to implement the radar if the bandwidth exceeds 1/10 to 1/8 of the carrier frequency (loosely defined by radar band).

Joe Gwinn

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Joseph Gwinn

On Jan 14, 2018, Phil Hobbs wrote (in article):

A RC lowpass with a RC Highpass sounds like one kind of 90-degree hybrid, which has come up before.

This sounds like something to model numerically, perhaps in the form of a

90-degree hybrid.

Thought it would be really profitable if only he could exceed the speed of light.

Joe Gwinn

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Joseph Gwinn

On Jan 14, 2018, sdy wrote (in article):

This is the core of many 90-degree hybrids, and is wideband enough for many radar applications.

This part is converging. As I?ve said in other emails, it sounds like something I should model in detail. Questions are transient response and group delay versus frequency.

Joe Gwinn

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Joseph Gwinn

On Wednesday, 17 January 2018 03:23:54 UTC, snipped-for-privacy@gmail.com wrote: nt:

I'm pretty sure that's correct, but feel free to point out where you think it isn't. Integration is the sum of the input signal over a time period. The thing is, the sum of the history parts is dc or lf, it's the now that's the ac or hf part of it, making it easy to separate the 2 again afterwards.

NT

Reply to
tabbypurr

I'm thinking the term "minimum phase system" needs to be used here.

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makolber

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