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In a noisy channel, the BER is often expressed as a function of the normalized carrier-to-noise ratio measure denoted Eb/N0, (energy per bit to noise power spectral density ratio), or Es/N0 (energy per modulation symbol to noise spectral density).
In the case of GPS, we have a data rate of 50 bit/s and a symbol rate of 1.023 Mchips/s. If each chip is considered a symbol, each symbol contains far less than one bit (50 bit/s / 1,023 ksymbols/s ≈ 0.000,05 bits/symbol). The complete collection of M possible symbols over a particular channel is called a M-ary modulation scheme.
As the description implies, is the signal energy associated with each user data bit; it is equal to the signal power divided by the user bit rate (not the channel symbol rate). If signal power is in watts and bit rate is in bits per second, E b {\displaystyle E_{b}} is in units of joules (watt-seconds).
It is, however, only able to modulate at 1 bit/symbol (as seen in the figure) and so is unsuitable for high data-rate applications. In the presence of an arbitrary phase-shift introduced by the communications channel , the demodulator (see, e.g. Costas loop ) is unable to tell which constellation point is which.
The symbol rate is related to gross bit rate expressed in bit/s. The term baud has sometimes incorrectly been used to mean bit rate , [ 3 ] since these rates are the same in old modems as well as in the simplest digital communication links using only one bit per symbol, such that binary digit "0" is represented by one symbol, and binary digit ...
When UI is used as a measurement unit of a time interval, the resulting measure of such time interval is dimensionless. It expresses the time interval in terms of UI. Very often, but not always, the UI coincides with the bit time, i.e. with the time interval taken to transmit one bit (binary information digit).
For example, if you have 1E-6 (one out of a million) BER, then test 10 million bits. ... it is that 'rate' usually implies a time-dependent function. A valid bit ...
A commonly used code encodes = eight-bit data symbols plus 32 eight-bit parity symbols in an =-symbol block; this is denoted as a (,) = (,) code, and is capable of correcting up to 16 symbol errors per block.