cc1101 Eb/No and BER

Nick,

It makes no sense to spec a Transmit/Reciever as you requested.   RF wireless talk in terms of Reciever sensitivity for a particular data rate.   This provides a packet error rate of 1%.   Then depending upon the transmit power and antenna pattern determines the distance of transmission.    One other point antenna height matters so this variable must be taken into account to determine the maximum line of sight.  If you working in doors there are formulas to predict the losses through walls etc.

It would be difficult to predict radio distance with your request.  Please consider using radio calculations to answer your questions.  The specs you are requesting are not for radio designs.

Regards

Thanks for the reply

Here is what I am doing. I will fully characterize   the antennas on an antenna range. I will calculate the free space loss between the transmitter and the receiver  to within a 1/10 of a decibel. Knowing these numbers I can calculate the signal coming in to the receiver. At This point one need to know how the receiver will perform. The usual specification is Energy per bit density in a 1 Hz Chanel  “Eb/No” at a cretin BER . Knowing the sensitivity of the receiver I will then boost the power of the transmitter sufficient to make the system work at the distance I need to cover. I am not constrained by the EIRP limits set under the FCC rules part 15.

The specification Eb/No is the industry standard of describing how a receiver/modem performs. The Eb/No is a function of the modulation type , the bandwidth of the receiver and the forward error detection .  If there is a another way please describe it to me. Please call me at 337 258 2527.

Thanks

nick

As I mention before we give you this in terms of % of packet error rate.   We specify it for the chip and not with the antenna.  The reason you have all these variables that effect it and most engineers want the spec for the radio not the system surrounding the design.   You can design a poor matchng network or place a de-tuned antnena and change your range and error rate. 

If you want to know the number in BER go to Google and enter BER to % Packet error rate this will give you all the equations to convert.  Then look in the data sheet for the sensitivity numbers for a given data rate.   All the circuitry and antenna only degrade the system and you are on your own to figure out each of those numbers. 

Nick, 

Some time ago I published a note here on the E2E on how to calculate the system performance of the receivers inside the CCxxx0 devices.

The link to the posting is found below, I hope you find it helpful.

http://e2e.ti.com/support/low_power_rf/f/155/p/49413/197797.aspx#197797

/TA

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Let me ask the question  a different way. Reference page 11 of the cc1101 data sheet the 433 mhz table. Using data rate of 250 kbs at deviation of 127 khz bw of 540 khz gmsk modulation it takes an input of -95 dbm. What the input be if the ½ rate fec is turned on?

nick

We don't spec or support the chip for working at that low of data rate.   Sorry

RRS said:

We don't spec or support the chip for working at that low of data rate.   Sorry

In your data sheet for the cc1101 page 11 the chip is spec at 250KBS . My question is what change in sensitivity happens as 1/2 rate FEC is turned on or off?

Nick