Should I use a filter, to filter out unwanted signals??

Thread Starter

Man10

Joined Jul 31, 2018
122
hypothetically if I were to build a device that receive video at 5.8 ghz, should I use a filter to filter out unwanted signals?
 

ronsimpson

Joined Oct 7, 2019
2,083
There are millions of radio signals in the air. (more than millions)
How are you going to pick which you want to receive?
A FM radio station can transmit 100,000 watts and you little 5.8ghz thing transmits a fraction of a watt. How are you going to not see the 30 strong FM signals in your area.
 

Thread Starter

Man10

Joined Jul 31, 2018
122
Okay. Should I use a bandpass filter or a low pass filter and a high pass filter to filter unwanted signals and detect 5.8 ghz signal.
 

Thread Starter

Man10

Joined Jul 31, 2018
122
Think about it. Are there signals and noise below 5ghz? Are there signals and noise above 5.8ghz?
I was just wondering if there is any reason or any possible reason to think that 1 approach is better than the other for any reason? If there isn't, just say yes or no.
 

BobTPH

Joined Jun 5, 2013
4,927
There is no chance you can build a 5.8GHz video receiver. This is not intended as an insult, I have been doing electronics for over 50 years. I could build s computer from scratch and write the compilers and OS for it. But I could not build a 5.8GHz video receiver.

Bob
 

Papabravo

Joined Feb 24, 2006
18,432
I was just wondering if there is any reason or any possible reason to think that 1 approach is better than the other for any reason? If there isn't, just say yes or no.
Like everything else in this field, the devil is in the details. Building a bandpass filter at 5.8 GHz is not likely to be realizable with lumped components. It might be a better strategy to down convert the 5.8 GHz signal and filter at a lower frequency. It is also just a bit out of my lane, like other posters have mentioned. I certainly wouldn't want to try it without some pretty fancy (expensive) equipment which I cannot afford and am unlikely to receive funding for anytime soon.
 

Thread Starter

Man10

Joined Jul 31, 2018
122
Depends.
Is this a wired or wireless connection?
Are there unwanted signals?
I mean is there any reason or any possible reason to think using a low pass filter and a high pass filter is a better approach than using a bandpass filter to filter unwanted signals and detect 5.8 ghz signal? Or is there any reason or any possible reason to think that using a bandpass filter is a better approach than using a high pass filter and a low pass filter to filter unwanted signals and detect 5.8 ghz? Just say yes or no. And it's a wireless connection.
 

Thread Starter

Man10

Joined Jul 31, 2018
122
Like everything else in this field, the devil is in the details. Building a bandpass filter at 5.8 GHz is not likely to be realizable with lumped components. It might be a better strategy to down convert the 5.8 GHz signal and filter at a lower frequency. It is also just a bit out of my lane, like other posters have mentioned. I certainly wouldn't want to try it without some pretty fancy (expensive) equipment which I cannot afford and am unlikely to receive funding for anytime soon.
I think I can buy a prebuilt 5.8 ghz bandpass filter on ebay.
 

Thread Starter

Man10

Joined Jul 31, 2018
122
I mean is there any reason or any possible reason to think using a low pass filter and a high pass filter is a better approach than using a bandpass filter to filter unwanted signals and detect 5.8 ghz signal? Or is there any reason or any possible reason to think that using a bandpass filter is a better approach than using a high pass filter and a low pass filter to filter unwanted signals and detect 5.8 ghz? Just say yes or no. And it's a wireless connection.
 

Papabravo

Joined Feb 24, 2006
18,432
Your question does not have the definitive answer you are looking for. If there is going to be a filter on the front end it should be a bandpass filter. A high pass or a low pass will only do half the job. this still leaves open the question of where in the chain the filter should be and how it should be implemented.
 

Thread Starter

Man10

Joined Jul 31, 2018
122
Your question does not have the definitive answer you are looking for. If there is going to be a filter on the front end it should be a bandpass filter. A high pass or a low pass will only do half the job. this still leaves open the question of where in the chain the filter should be and how it should be implemented.
I mean the signal passes through a low pass filter first, then the signal passes through a high pass filter.
 

Thread Starter

Man10

Joined Jul 31, 2018
122
When engineers build a video receiver that wirelessly receives video, they don't pass the signal through a low pass filter first, then pass the signal through a high pass filter or do they?
 

BobTPH

Joined Jun 5, 2013
4,927
A wireless tuner IS a very sharp bandpass filter and a detector. Are you talking about an additional filter or the tuner itself?

Bob
 

Thread Starter

Man10

Joined Jul 31, 2018
122
A wireless tuner IS a very sharp bandpass filter and a detector. Are you talking about an additional filter or the tuner itself?

Bob
For example to build a video receiver that wirelessly receive video at 433 Mhz, he wouldn't pass the signal through a low pass filter with cutoff frequency at 433 Mhz, which filters frequencies below 433, first, then pass the signal through a high pass filter with a cutoff frequency at 433 Mhz, which filters frequencies above 433Mhz or would he? The system has 2 filters, one for filtering frequencies below 433 Mhz and the other filter for filtering frequencies above 433 Mhz.
 
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