#Error probability ask fsk psk code#
#Error probability ask fsk psk Bluetooth#

This requires the receiver to be able to compare the phase of the received signal to a reference signal – such a system is termed coherent (and referred to as CPSK).ĬPSK requires a complicated demodulator, because it must extract the reference wave from the received signal and keep track of it, to compare each sample to. The demodulator, which is designed specifically for the symbol-set used by the modulator, determines the phase of the received signal and maps it back to the symbol it represents, thus recovering the original data. Each pattern of bits forms the symbol that is represented by the particular phase. Usually, each phase encodes an equal number of bits. PSK uses a finite number of phases, each assigned a unique pattern of binary digits.

#Error probability ask fsk psk Bluetooth#

It is widely used for wireless LANs, RFID and Bluetooth communication.Īny digital modulation scheme uses a finite number of distinct signals to represent digital data. The modulation is accomplished by varying the sine and cosine inputs at a precise time. The staircase like waveforms represents approximation to the analog waveforms (after quantization distortion has been introduced.Phase-shift keying ( PSK) is a digital modulation process which conveys data by changing (modulating) the phase of a constant frequency reference signal (the carrier wave). This is how one can generally obtain better fidelity at the cost of more transmission bandwidth Next Fig.2.18 compares the quantization of a strong versus a weak signal for uniform and non-uniform quantization. In real time communication message must not be delayed, and bits must move faster. More on quantization… Now, each sample will be represented by 4-bits, consequently we would have high data rates, improved signal quality or fidelity.

If we double the number of levels to 16, what supposed to be the benifit? Thus increasing the number of levels will reduce the quantization noise.

What could we do to improve the fidelity? We know that process of quantization replaces the true signal with an approximation (i.e., adds quantization noise). Also suppose that when we listen to the music in digital form, it’s quality is not good. More on quantization… Suppose that analog signal is a musical, which is sample at a Nyquist rate (fs ≥ 2fm). Note that each sample is assigned to one of eight levels or a three bit PCM sequence.

#Error probability ask fsk psk code#

Beneath the analog waveform x(t) are seen four representations of x(t) as follows:- The natural sample values, quantized sample values, the code numbers and the PCM sequence. Each sample of the analog signal is assigned to the quantization level closest to the value of sample. More on quantization… The ordinate in fig.2.16 is labeled with quantization levels and their code numbers. More on quantization Block diagram of formatting and transmission of baseband signals Fig.2.2. M-ary orthogonal pulses… Cross correlation between any two rows is zero for e.g. M-ary orthogonal pulses Fig.3.34 shows one possible set of M orthogonal signals For example we may use M orthogonal pulses φ1(t), φ2(t), …, φM(t), with the following property:. There are other possible ways to structure M waveforms.Fig.3.33 shows just one possible M-ary scheme (multi-amplitude signaling).The PSK, being polar, requires 3dB less power than ASK or FSK for the same noise immunity i.e.Conclusion is that polar signaling is the most efficient scheme from the point of view of the noise immunity.Note that the bandwidth of FSK is higher than ASK or PSK.Power spectral density (PSD)…of ASK,PSK and FSK