usually the bandwidth in computer network is calculated as the difference between the upper frequency and the lower frequency. This difference can be the same for several ranges. for eg. 65 Mhz - 60 Mhz (5MHz) and 15 MHz - 10 MHz (5MHz). But a channel capable of sending signals the range 60-65 is much higher than the channel sending signals at 10-15 range. Then how can we say that the bandwidth the same ???
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The bandwidth is the same because the band between frequencies is the same. It is quite literally the * band * * width * which has nothing to do with the base frequency. Frequency is frequency, and all "frequency" means is the number of cycles per second in the wave. You might be able to make better use of the properties of particular frequencies and thus make more effective use of the band width available, but that is distinct and different to the bit-rate that a particular signal modulation method can get from a particular bandwidth.Mokubai– Mokubai2024-06-08 18:01:58 +00:00Commented Jun 8, 2024 at 18:01
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1It seems to me that you have a confused understanding of bandwidth - I suggest you check out en.wikipedia.org/wiki/Bandwidth , where you seem to have the first two "mixed up" - the first is about Analog / Radio bandwidth, the second about communications bandwidth i.e. in computer networks.Hannu– Hannu2024-06-08 18:51:48 +00:00Commented Jun 8, 2024 at 18:51
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2You've described radio channel bandwidth (which is measured in Hertz and even applies to analog, completely non-digital radio transmissions), not computer network bandwidth, which is measured in bits per second, doesn't always happen over radio channels, and when it does happen over radio channels, is dependent on the signaling / modulation scheme involved. Network throughput is called "bandwidth" in analogy to radio channel bandwidth, but they are not as closely related as the shared name might imply.Spiff– Spiff2024-06-08 18:55:00 +00:00Commented Jun 8, 2024 at 18:55
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I believe that you are misunderstandiing the concepts of Channel, analog signals and digital signals
a signal is a time-varying quantity that represents information being transmitted from one point to another.
- Bandwidth of an analog signal is defined as the range of frequencies that the composite analog signal carries. So Yes, 2 analog signals of ranges 60MHz-65MHz and 10-15Mhz have the exact same bandwidth, as they carries the same range of frequencies.
- Bandwidth of a digital signal defined as the maximum bit rate of the signal to be transmitted, and is measured in bits per second.
A channel is the medium through which the signal carrying information will be passed. The channel bandwidth determines the type of signal to be transmitted i.e. analog or digital.
- In terms of analog signal, bandwidth of the channel is the range of frequencies that the channel can carry
- In terms of digital signal, bandwidth of the channel is the maximum bit rate supported by the channel. i.e. the maximum amount of data that the channel can carry per second.
- Channels can introduce various effects on the signal such as attenuation, distortion, noise, and interference. This is why the "same signals" may not have the same "Computing network performance" (i try use your unclear words) depending on the channel used.
Now that we agreed on the same basis, lets discuss about the MAXIMUM DATA RATE OF A CHANNEL
- For Noiseless channels (the theory that almost never happens) : we use the "Nyquist Bit Rate" formula [Bitrate = 2 x Bandwidth x Log2 x L] (L is the signal level).
- For Noisy channels (our real cursed world XD) : we use the "Shannon capacity" [Capacity=bandwidth X log2 (1 +SNR)] (SNR is the Signal-to-Noise ratio).
- For analog signals (theoritically), channels carrying signals at different frequencies ranges but having equals bandwidth will share the same Bitrate. However (in the real world), the "strength" (or capacity or bitrate or height to take your words) of a channel also depends on the underlying technology and its capacity to handle noise. This may depend on various factors (temperature, distance & frequency highness, a truck crashing right to your channel XD, etc...) and an higher frequency may probably reduce the channel SNR on short distances.
- For digital signals, channels at higher frequency ranges are potentially able to support signals at higher frequencies, and signals at higher frequencies means higher data sampling leading to a bigger bandwidth (in bits per seconds).
Conclusion Going back to your question
One could say that a channel carrying digital signals at higher frequencies will have better peformance (in terms of data rate) as the signals will probably have bigger bandwidth due to the signal data sampling.
For analog signals, one could say that calling your mate with your mobile fone and telling him your address and credit card number will takes exactly the same amount of time whether your are calling him on a 10Mhz or 60Mhz frequency XD (little joke).
