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Expert Talk: What Is Bandwidth and Why Do I Care?

amirm

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What Is Bandwidth and Why Do I Care?

Zoom Meeting: Thursday, November 17th, 2022, 6PM PST (UTC -8)
image linked to jj_491x492.jpg
To attend this FREE event, Click Here to access Eventbrite for this event.
NOTE: Ticket sales end when the meeting begins.

Have you ever wondered
why your digital audio system can not "miss" that spike that happens entirely between samples? Have you ever wondered how you can get subsample time resolution in digital systems, without even trying? Well, here's the answer, signal bandwidth.

This talk explains what restricting the bandwidth of a signal does, necessarily, to the signal. To the first question above, no, that signal can not ever even exist unless it's many, many times outside the bandwidth of the digital system you're examining. To the second question, no, you don't have any "stairsteps" and no, you don't have any "edges" in the reproduced signal.
We'll start with a single "impulse," and show what system bandwidth looks like, why filters look the way they do, and how the output of a digital signal can not have any edges. All of this is due to the required bandwidth limitation in a sampled data system. Along the way, a few bits of disinformation will be revealed and dismissed for what they are.

About James D. (jj) Johnston​

James D. (jj) Johnston is Chief Scientist of Immersion Networks. He has a long and distinguished career in electrical engineering, audio science, and digital signal processing. His research and product invention spans hearing and psychoacoustics, perceptual encoding, and spatial audio methodologies.
He was one of the first investigators in the field of perceptual audio coding, one of the inventors and standardizers of MPEG 1/2 audio Layer 3 and MPEG-2 AAC. Most recently, he has been working in the area of auditory perception and ways to expand the limited sense of realism available in standard audio playback for both captured and synthetic performances.
Johnston worked for AT&T Bell Labs and its successor AT&T Labs Research for two and a half decades. He later worked at Microsoft and then Neural Audio and its successors before joining Immersion. He is an IEEE Fellow, an AES Fellow, a NJ Inventor of the Year, an AT&T Technical Medalist and Standards Awardee, and a co-recipient of the IEEE Donald Fink Paper Award. In 2006, he received the James L. Flanagan Signal Processing Award from the IEEE Signal Processing Society, and presented the 2012 Heyser Lecture at the AES 133rd Convention: Audio, Radio, Acoustics and Signal Processing: the Way Forward. In 2021, along with two colleagues, Johnston was awarded the Industrial Innovation Award by the Signal Processing Society "for contributions to the standardization of audio coding technology."
Mr. Johnston received the BSEE and MSEE degrees from Carnegie-Mellon University, Pittsburgh, PA in 1975 and 1976 respectively.
This is a Zoom meeting, starting at 6pm PST (UTC-8).

RSVP​

To attend this FREE event, Click Here to access Eventbrite for this event.
NOTE: Ticket sales end when the meeting begins.

THIS EVENT IS FREE, OPEN TO ALL, AND AES MEMBERSHIP IS NOT REQUIRED
Dan Mortensen

AES PNW 2022-2023 Section Chair

n.b. The material presented at our meetings is the opinion of the presenter and not necessarily that of the Society. You are encouraged to conduct your own research and to form your own opinions before adopting the presented material as Truth.
 

Scytales

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Thanks for the info. :)
 

Beershaun

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Have signed up!
 

pseudoid

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Thank you for the notification, @amirm.
Hallelalujah! Importance of bw hopefully will get uncloaked.:)
Sometimes, we seem to overlook and/or don't pay enough attention to bw limiting... whether of the intended signal or measuring thereof.
'Out-of-band' should not be 'out-of-mind', even if only audio-quality is to be considered!
 

AdamG247

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For those of you who may not know. This is being presented by our very own illustrious and learned ASR Member @j_j . Show up and support one of our own Members.

 

Koeitje

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Considering this is at 02:00 (AM) CET, is there a way to watch back at a later time?
 
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j_j

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Considering this is at 02:00 (AM) CET, is there a way too watch back at a later time?
After a couple of week delay for processing, the talk should be available as recorded. We do 6PM PST because that doesn't block out east coast USA people, and we can't go earlier because that would mean west coast US people are at work. I understand your frustration.
 

AdamG247

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After a couple of week delay for processing, the talk should be available as recorded. We do 6PM PST because that doesn't block out east coast USA people, and we can't go earlier because that would mean west coast US people are at work. I understand your frustration.
We will try to do a follow up post and provide a Link to the Recorded Talk once released.
 

KiyPhi

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After a couple of week delay for processing, the talk should be available as recorded. We do 6PM PST because that doesn't block out east coast USA people, and we can't go earlier because that would mean west coast US people are at work. I understand your frustration.
I love your lectures. I'll end up having to watch this one in the archives since Thursdays are my late days at the clinic. Good to know the timeframe I can catch it though, thanks!
 

pseudoid

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Will the details about how to join the Zoom talk be made available at a later date upon registration?
Will there be alternative methods (yt? etc.) to watch/listen to the @j_j' presentation w/o Zoom and w/o participating in the Q&A?
 

sam_adams

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For those of us who cannot attend because of timezone or work; will there be a recording of the meeting made so we won't lose out on what will sure to be a very enlightening event?
 
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amirm

amirm

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pseudoid

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If you click on one of them, below the ribbon of few images there is a youtube video link.
Thank you and I could post here for others to use but something tells me to keep it to myself and not advertise the link.
 

restorer-john

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For those of you who may not know. This is being presented by our very own illustrious and learned ASR Member @j_j . Show up and support one of our own Members.

Only if he wears that insane shirt.

jj_491x492.jpg
 
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