demodmap.hlp

数字通信第四版原书的例程

ask_help_begin
DEMODMAP Demap for M-ary amplitude shift keying (ASK) demodulation.
       Z = DEMODMAP(Y, Fd, Fs, METHOD, M), METHOD = 'ask', demaps a modulation
       mapped signal (by using MODMAP).  Each column of the input signal Y is
       independent processed. By columnwise, Y has sample frequency Fs (Hz). 
       The output signal has sample frequency Fd (Hz). Fs must greater than
       Fd. Fs/Fd should be a positive integer. The M-ary number for the
       ASK is M. The output symbols are integers is in range [0, M-1], which
       has the closest distance to the input value. When Fd is a two element
       vector, the second element is an integer that specifies the offset in
       choosing the decision point Fd(2)/Fs. The default offset is zero.

       The constellation of the ASK can be plotted by using MODMAP('ask', M).
ask_help_end

psk_help_begin
DEMODMAP Demap for M-ary phase shift keying (PSK) demodulation.
       Z = DEMODMAP(Y, Fd, Fs, METHOD, M), METHOD = 'psk', demaps a modulation
       mapped signal (by using MODMAP). The output signal Z is a even column
       matrix with the odd column as in-phase component and second column as
       quadrature component. Each column of the input signal Y is
       independently processed. Columnwise, Y has sample frequency Fs (Hz).
       The output signal has sample frequency Fd (Hz). Fs must be greater than
       Fd. Fs/Fd should be a positive integer. The M-ary number for the PSK
       is M. The output symbols are integers is in range [0, M-1], which has
       the closest distance to the input value. When Fd is a two element
       vector, the second element is an integer that specifies the offset in
       choosing the decision point Fd(2)/Fs. The default offset is zero.

       The constellation of the PSK can be plotted by using MODMAP('psk', M).
psk_help_end

qas_help_begin
DEMODMAP Demap for M-ary quadrature amplitude shift keying (QASK) demodulation.
       Z = DEMODMAP(Y, Fd, Fs, METHOD, M), METHOD = 'qask', demaps a
       modulation mapped signal (by using MODMAP) using QASK square 
       constellation. The output signal Z is a even column matrix with the
       odd column as in-phase component and second column as quadrature
       component. Each column of the input signal Y is independently
       processed. Columnwise, Y has sample frequency Fs (Hz). The output
       signal has sample frequency Fd (Hz). Fs must be greater than Fd.
       Fs/Fd should be a positive integer. The M-ary number for the
       QASK square constellation is M. The output symbols are integers is
       in range [0, M-1], which has the closest distance to the input value.
       When Fd is a two element vector, the second element is an integer
       which specifies the offset in choosing the decision point Fd(2)/Fs.
       The default offset is zero.

       The constellation of the PSK can be plotted by using MODMAP('qask', M).

       Z = DEMODMAP(Y, Fd, Fs, METHOD, In_Phase, Quad), METHOD = 'qask/arb'
       demaps a modulation mapped signal (by using MODMAP) Y using the QASK
       method with arbitrary constellation. The arbitrary constellation is 
       defined in the variables In_Phase and Quad. The constellation point for
       message I is defined by In_Phase(I+1) and Quad(I+1), which specifies
       the in-phase and quadrature component respectively.

       The constellation of the arbitrary constellation QASK can be plotted by
       using MODMAP('qask/arb', In_phase, Quad).

       Z = DEMODMAP(Y, Fd, Fs, METHOD, NIC, AIC, PIC, NUM, DEN),
       METHOD = 'qask/cir', demaps a modulation mapped signal (by using
       MODMAP) using QASK circle constellation. The numbers in circle,
       amplitude in circle, and a signature phase in circle are defined
       in NIC, AIC, and PIC respectively. The three vectors NIC, AIC, and
       PIC have the same length. The constellation in each circle is evenly
       distributed in each circle with one of the points having its phase as
       the signature phase. When PIC is not given, PIC is assumed to be an
       all zero vector. When AIC is not given, the default value 
       AIC = [1:length(NIC)] is used.

       The constellation of the QASK can be plotted by using
       DMOD('qask/cir', NIC, AIC, PIC)
qas_help_end

fsk_help_begin
DEMODMAP Demap for M-ary frequency shift keying demodulation.
       Z = DEMODMAP(Y, Fd, Fs, METHOD, M, Tone), METHOD = 'fsk', demaps a 
       modulation mapped signal (by using MODMAP). The input signal has sample
       frequency Fs. The output signal has sample frequency Fd. It is required
       that Fs > Fd. Fs/Fd must be a positive integer. The M-ary number for
       the FSK is M. The output the digit is in range [0, M-1] which has the
       closest distance to the decision point. When Fd is a two element vector,
       the second element is an integer that specifies that the offset in
       choosing the decision point is Fd(2)/Fs. The default offset is zero.
       The constellation of the FSK can be plotted by using 
            MODMAP('fsk', M, Tone).

       Z = DEMODMAP(Y, Fd, Fs, METHOD), METHOD='fsk/max', demaps the
       correlation matrix Y by choosing the maximum correlation value as the
       demapping digit. The digits in the output column vector are in range
       [0, M-1], where M is the column number of Y.
fsk_help_end
msk_help_begin
DEMODMAP Demap for minimum shift keying demodulation.
       Z = DEMODMAP(Y, Fd, Fs, METHOD), METHOD = 'msk', demaps a modulation
       mapped signal (by using MODMAP). The input signal has sample frequency
       Fs. The output signal has sample frequency Fd. It is required that
       Fs > Fd. Fs/Fd must be a positive integer. 'msk' is a special case of
       'fsk' with M-ary number as 2 and tone space as Fd. When Fd is a two
       element vector, the second element is an integer that specifies that
       the offset in choosing the decision point is Fd(2)/Fs. The default
       offset is zero.

       Z = DEMODMAP(Y, Fd, Fs, METHOD), METHOD='fsk/max', demaps the
       two-column correlation matrix Y by choosing the maximum correlation
       value as the demapping digit. The digit in the output column vector
       are binary number.
msk_help_end
sam_help_begin
DEMODMAP Demap a signal from sample frequency Fs to sample frequency Fd.
       Z = DEMODMAP(Y, Fd, Fs, METHOD), METHOD = 'sample', converts sampling
       frequency Fs signal Y into sampling frequency Fd signal Z. When Y is
       a matrix, the function processes the input column by column. The output
       Z will have the same number of column number as Y. It is required that
       Fs>Fd. Fs/Fd must be an integer. When Fd is a two element vector, the
       second element is an integer that specifies that the offset for the
       decision point is Fd(2)/Fs. The default offset is zero.
sam_help_end
eye_help_begin
DEMODMAP Eye-pattern plot.
       DEMODMAP(Y, Fd, Fs, METHOD), METHOD = 'eye', plots each column element
       in Y by eye-pattern plot. When Y is a multi-column matrix, the color
       for the columns are in the order of yellow, megenta, cyan, red, green,
       blue. The time distance between two successive rows is 1/Fs. The
       plot time window is 1/Fd. It is required that Fs > Fd. Fs/Fd must be an
       integer. When Fd is a two element vector, the second element is an
       integer that specifies that the offset for the beginning point is
       Fd(2) / Fs. The default offset is zero.
eye_help_end
sca_help_begin
DEMODMAP Scatter plot.
       DEMODMAP(Y, Fd, Fs, METHOD), METHOD = 'scat', plots sample frequency Fs
       signal in Y by scatter plot. The time distance between two successive
       rows in Y is 1/Fs. The function takes a point to plot at sample
       frequency Fd. It is required that Fs > Fd. Fs/Fd must be an integer.
       When Fd is a two element vector, the second element is an integer
       that specifies that the offset for the plotting point is Fd(2)/Fs.
       The default offset is zero. When Y is a multi-column matrix, the colors
       for the columns are in the order of yellow, magenta, cyan, red, green,
       and blue.

       DEMODMAP(Y, Fd, Fs, METHOD, SYMBOL) selects the plot symbol. SYMBOL can
       be one of the following characters: '.', '*', '+', 'x', 'o'.
sca_help_end