How to determine that a component is narrowband or wideband?

[masadi]

how to determine that a component is narrowband or wideband??
is it determined by a laboratory measurement ?
or any mathematical calculation for it??

give me some explanation about that for directional coupler

thanks a lot

 

[brmadhukar]

wideband narrowband

Hi,
The component data sheets normally indicate the bandwidth. Usually narrowband components will be tuned and shall have better noise figure than the wideband components.

The DCs that I have used were Wideband for me. They work form DC to 2.5GHz.
I used Agilent components.

B R
M

 

[sergio mariotti]

narrow band wide band

Generally speaking:
narrowband stay for few% to 10 or 15%.
Wideband stay for bandwidth up to 1 octave
Then larger bandwidths are called "multioctave" or "ultra wide".

Often, the best technical performances are acheived by narrowband systems while best economic performaces are acheived by larger bandwidth.

 

[masadi]

is broadband bigger than narrow band in bandwidth

OK thanks..

But what's 1 octave?

Added after 25 seconds:

OK thanks..

But what's 1 octave?

 

[djalli]

wideband broadband narrowband bandwidth

when frequency 1MHz is increated by 1 decade it means frequency is 10MHz

when frequency 1MHz is increased by 1 octave it means frequency is 2MHz

In RF when operating spectrum of certain operating mode is considered narrow-band then (let's make it 1GHz example) spectrum is between 750MHz to 1.25GHz wide.

and as sergio marrioti was saying is considered wide-band when spectrum is 600MHz to 4GHz wide at least.

 

[multanova51]

narrowband components

Hi guys....

All is relative....
Sometimes a signal bw of 300 kHz or lower is considered wideband...
It all depends on your WANTED bandwidth.
I am not completely sure what the original question has for background.
In general if a signal is narrowband or broadband can be easely determined on a spectrum analyser. If you take eg a CW signal on a sspectrum anlyser, the amplitude does not vary when you change the analyser b/w. For a wideband signal the signal amplitude DOES CHANGE and may change a lot while varying the analyser b/w.
I hope this brings an alternative view to the statements in above replies.

rgds
from Mike

 

[lakeoffire]

what is narrowband

Yes, this is a relative issue. One possible way to tell a system is a wideband or a narrowband one is to look at the ratio of the bandwidth to the center frequency.

 

[SkyHigh]

narrow band versus wideband communications

Dear Masadi,

In Digital Communications, Wideband is a bandwidth class between 64Kbps and 1.544Mbps whereas Narrowband is only up to 64Kbps. Should a communication device, a circuit or a channel of a certain network (usually wireless) exhibit a bandwidth of at least 64Kbps, it is termed Wideband. It is however not the carrier frequency to determine a device, a circuit or a channel as Wideband. Thus a Wideband entity can also range from DC to 32KHz, assuming 2bps.

In RF and Analog circuits, Gain-Bandwidth Product is a basic relationship. 1 Octave specifies an 2 times increase in bandwidth for a device or a circuit at the expense of a reduced gain. This only specifies a wider band, hence not necessary a Wideband. Therefore an entity subjected to 1 Octave change in bandwidth must first satisfy a bandwidth of at least 64Kbps to be considered Wideband.

 

[boy]

wideband channel greek

I may add. in the mobile communication, coherence bandwith of the channel determines whether the signal is broadband or not. let say 30 KHz BW signal may be considered as a narrowband in one channel but not in other channels.

 

[SkyHigh]

narrow band o2 change wideband

Yes, agreed.

It's the bandwidth that can usefully deliver data (in bps) rather than the allocated bandwidth, which may not be 100% utilised, that determines wide/narrowband.

To second and support your claim, Broadband is divided into N channels, each is usually a narrowband. However what actually determine Broadband is that the allocated bandwidths are quite specific such that Channel 1 and 4 carry Data, Channel 2 and 5 carry Audio and Channel 3 and 6 carry Video. Channel 1, 2 and 3 are Downlink channels and Channel 4, 5 and 6 are Uplink channels.

 

[evoplus]

narrow-band wide-band

Hi everyone,

I still have doubt in understanding of narrowband and wideband. I agreed that it depends on how the system is defined for. Let's say that if I'm supposed to design a wideband system say 26-40GHz. So how do we ensure that the design would be correct? How do I see it by looking at the ratio of the bandwidth to the center frequency only? Are there any other way to justify this? Thanks.

 

[Rayengine]

broadband, narrowband, wideband

Any professional definition between narrowband and wideband?