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# Bandwidth

## Bandwidth

(OP)
What is the meaning of Bandwidth and what can I do with it?

Thank you.

William H. Bernhart, P.E.

I work as a development engineer for AMP - Tyco Electronics located near Harrisburg, PA. I help design interconnections / electrical connectors for aerospace applications.

Replies continue below

### RE: Bandwidth

Bandwidth, the amount of data that can be transmitted in a given period over a transmission channel such as a radio transmitter, satellite dish, or the wiring that connects one computer to another. Bandwidth typically is expressed in cycles per second (hertz) or bits per second (bps).

### RE: Bandwidth

(OP)
Thank you...

William H. Bernhart, P.E.

I work as a development engineer for AMP - Tyco Electronics located near Harrisburg, PA. I help design interconnections and electrical connectors for aerospace applications.

### RE: Bandwidth

I agree that the bandwidth is the measurement of information/time. But the bandwidth is the width of a channel in hertz. The bits/sec is a rating of speed of information transfer. You see, in order for a signal to be sent in bits it has to be a digital signal( 1s or 0s) as opposed to an analog signal. If you want to learn more William, just feel free to write another question:)
Steve M.

### RE: Bandwidth

Suggestion:
The connectors, etc., to function in proper bandwidth, shall be rated for that bandwidth (in Hz, kHz, MHz, or GHz). E.g. telephone copper wire and associated connectors have smaller bandwidth than fiber optics line and associated connectors. Data sheets from manufacturer or inquiry over the manufacturer tech support should provide the missing bandwidth data. In some cases, it is possible to be slightly below a bandwidth limit, if this is possible/tolerable and/or justified otherwise.

### RE: Bandwidth

(OP)

William H. Bernhart, P.E.

I work as a development engineer for AMP - Tyco Electronics located near Harrisburg, PA. I help design interconnections and electrical connectors for aerospace applications.

### RE: Bandwidth

I would like to know the prcise definition of channel in cellular technology and for a cell site can you use the same frequency for the different sectors in the cell.

B.A

### RE: Bandwidth

What about in satellite communication, what is the relation of your transmission rate, symbol rate and bandwidth a particular carrier can occupy in a transponder?

### RE: Bandwidth

Bandwidth of a satellite carrier, much like any other, is determined by the information rate, coding implementation, and modulation scheme.  1/2 rate coding produces two symbols for every information bit, 3/4 rate produces four symbols per every three information bits, etc.  As for modulation, QPSK is spectrally more efficient than BPSK, etc.  Modern satellite modems are up to QAM 16.  Very efficient.  Of course, the transponder itself has limits.  Typically 36 MHz per transponder where communications satellites are concerned.

### RE: Bandwidth

svermill, do you have a formula that relates symbol rate, info bit rate, FEC rate to TX bandwidth? Can u post it here?

etpineda

### RE: Bandwidth

etpineda,

With regard to symbols vs. bits, the math is simple.  1/2 coding equals two symbols per information bit.  3/4 coding equals four symbols per 3 information bits and so on.  There isn't any fixed formula for calculating bandwidth.  You have to know several things about your carrier (modulation type chief among them!) before you can make that calculation.  There are plenty of software applications for calculating link budgets.  Check out the Intelsat website for one.

Scott

### RE: Bandwidth

thanks

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