191–200 of 249 posts
I was almost through the checkout flow last week before I realized that this configuration only supports a relatively narrow frequency range. I work primarily in sub-GHz radio. Please wake me up when they launch their LoRa version, that would be an instant purchase for me.
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We've got the switching noise nailed down. Fortunately the LVDS jitter doesn't affect the sigma delta too badly because that impacts proportional to baseband frequency which is largely filtered out by the decimation filters beyond 40 MHz.. With a total of eight ADCs per QuadRF, you can see we are getting huge savings by being custom! While the per-ADC ENOB is 7-8 bits, another nice thing about phased arrays is that t…
I like to think of myself as pretty well-versed when it comes to hardware and software and even some RF. But this conversation has me hitting search a lot, lol. It's fascinating reading experts talk about a domain I have less experience in.
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Yeah I think it is at every defense show, but that doesn't mean it makes it to the front lines. Defense show = super expensive. This is cheap.
Homing in on sources of electromagnetic transmissions has been a thing since at least the BV246 in 1943. The first phased array systems date back to 1905. We have had some time to productionize this. Hell, the "PA" in "PATRIOT missile" stands for "Phased Array".
The new thing is that it's available for purchase for a reasonable price.
One day I want to build something like this, except for sound. It would be great to get a heading and distance for where a sound is coming from. This could be both for small scale things (e.g. which part of this is squeaking?) or large scale (e.g. is that booming noise coming from the construction a few blocks away?)
Making the hardware is fairly achievable without having to do fancy things. but if you want >8 channels you'll need to make some custom interface hardware.
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Fluke has made an acoustic imager for a while now. It is used for detecting leaks: https://www.fluke.com/en-us/product/industrial-imaging/fluke...
Has anyone tried acoustic imaging for water leaks inside walls? I live in a multi-floor 1900s Victorian. A leak can affect several units, and tracing the source can mean opening walls or floors in multiple places, and coordinating access has been getting harder with less WFH. Could one of these tools help map water pipe routes and trace a leak, or are they only going to be useful for air and gas leaks?
There is a man call leak detective, who hunts for leaks in the UK. one tool he has is shutting off the water and filling the pipes with gas and using either sound or gas detector to pin down leaks.
A lot of the time he just listens though.
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The army has one of these for sniper triangulation, and Boeing made a civilian version for optimizing sound dampening on the 787. I don’t know if they kept doing that on subsequent planes but I would expect so given how enthusiastic they were about being able to apply the weight budget to greater effect. You need really high clock rate sensing to differentiate the arrival time for sound from microphone arrays where t…
A nanosecond? The speed of sound at sea level in dry air is approximately 330m/s. So at say 3.3 kHz, the rough logarithmic middle of the audible spectrum, K=2π/lambda is 2π/0.1 m=20 π rad/m. A phase difference from a source difference k. ∆r would therefore likely be far more easily resolved than that for many physical ∆rs then, no?