ask_help_begin
MODMAP Maps for M-ary amplitude shift keying (ASK) modulation.
       Y = MODMAP(X, Fd, Fs, METHOD), METHOD = 'ask', maps a sample frequency
       Fd digital input signal X to a sample frequency Fs output signal Y.
       Fs/Fd should be a positive integer. The size of the resulting signal Y
       is Fs/Fd times that of the original signal X. All elements in X are
       non-negative integers in range [0, M-1]. M = 2^K such that 
       max(X) < 2^K, where K is the minimum integer satisfies max(X) < 2^K.
       The mapped signal in Y has its value in range [-1 to 1].

       Y = MODMAP(X, Fd, Fs, METHOD, M), METHOD = 'ask', specifies the
       M-ary number M.

       MODMAP(METHOD, M), METHOD = 'ask', plots the ASK constellation.

       The output Y can be directly input to COMMOD with METHOD='amdsb-tc',
       'amdsb-sc', or 'amssb' for signal modulation. The mapped Y can also be
       modified by using Y =[Y Y*0] as input to COMMOD with METHOD = 'qam'.
ask_help_end

psk_help_begin
MODMAP Maps for M-ary phase shift keying (PSK) modulation.
       Y = MODMAP(X, Fd, Fs, METHOD), METHOD = 'psk', maps a sample frequency
       Fd digital input signal X to a sample frequency Fs output signal Y.
       Fs/Fd should be a positive integer. The size of the resulting signal Y
       is Fs/Fd times that of the original signal X. All elements in X are
       non-negative integers in range [0, M-1]. M = 2^K such that 
       max(X) < 2^K, where K is the minimum integer satisfies max(X) < 2^K.
       The mapped signal in Y satisfies Y(i, 1)^2 + Y(i, 2)^2 = 1 for any
       valid i.

       Y = MODMAP(X, Fd, Fs, METHOD, M), METHOD = 'psk', specifies the
       M-ary number M.

       MODMAP(METHOD, M), METHOD = 'psk', plots the PSK constellation.

       The mapped Y can be directly input to COMMOD with METHOD='QAM' for 
       signal modulation.
psk_help_end

qask_help_begin
MODMAP Maps for M-ary quadrature amplitude shift keying (QASK) modulation.
       Y = MODMAP(X, Fd, Fs, METHOD), METHOD = 'qask', maps a sample frequency
       Fd (Hz) input digital signal X into in-phase and quadrature components
       in sample frequency Fs (Hz) output signal Y using square QASK map. 
       Fs/Fd should be a positive integer. The output signal Y is a two column
       matrix with the first column as in-phase component, and the second
       column as quadrature component. The row number of Y is Fs/Fd times the
       length of the original digit signal X. All elements in X are
       non-negative integers in range [0, M-1]. M = 2^K, such that 
       max(X) < 2^K, where K is the minimum integer that satisfies 
       max(K) < 2^K. The output maximum numbers are as follows:
           M = 2,   maximum = 1;   M = 4,   maximum = 1;
           M = 8,   maximum = 3;   M = 16,  maximum = 3;
           M = 32,  maximum = 5;   M = 64,  maximum = 7;
           M = 128, maximum = 11;  M = 256, maximum = 15;

       Y = MODMAP(X, Fc, Fs, METHOD, M), METHOD = 'qask', specifies the range
       of the input digits are in range [0, M-1].

       MODMAP(METHOD, M), METHOD = 'qask', plots QASK square constellation
       with the specified M-ary number M.

       Y = MODMAP(X, Fc, Fs, METHOD, In_Phase, Quad), METHOD = 'qask/arb',
       maps a sample frequency Fd (Hz) input digital signal X into the
       in-phase and quadrature components of the sample frequency Fs (Hz) 
       output signal Y using user-defined arbitrary constellation. The
       arbitrary constellation is defined in the input variable In_Phase and
       Quad. For a digit input I, the in-phase and quadrature map are 
       In_Phase(I+1) and Quad(I+1) respectively.

       MODMAP(METHOD, In_Phase, Quad), METHOD = 'qask/arb' plots the mapping
       constellation defined in the pair vector In_Phase, Quad.

       Y = MODMAP(X, Fc, Fs, METHOD, NIC, AIC, PIC), METHOD = 'qask/cir',
       maps a sample frequency Fd (Hz) input digital signal X into the
       in-phase and quadrature components of the sample frequency Fs (Hz) 
       output signal Y using circle constellation. The constellation for
       the modulation is defined by circle form, with the number, amplitude,
       and a signature phase defined in vectors NIC, AIC, PIC respectively. 
       The three vectors have the same length. The constellation in each ring 
       is evenly distributed in each ring with one of the point placed on the
       specified signature phase point. 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)] will be used.

       MODMAP(METHOD, NIC, AIC, PIC), METHOD = 'qask/cir' plots the circle
       form constellation defined in NIC, AIC, and PIC.
       
       The mapped Y can be directly input to COMMOD with METHOD='QAM' for 
       signal modulation.
qask_help_end
fsk_help_begin
MODMAP Maps for M-ary frequency shift keying (FSK) modulation.
       Y = MODMAP(X, Fd, Fs, METHOD), METHOD = 'fsk', maps a sample frequency
       Fd digital input signal X to a sample frequency Fs output signal Y.
       Fs/Fd should be a positive integer. The size of the resulting signal Y
       is Fs/Fd times that of the original signal X. All elements in X are
       non-negative integers in range [0, M-1]. M = 2^K such that 
       max(X) < 2^K, where K is the minimum integer satisfies max(X) < 2^K.
       The mapped signal in Y has its value in range [-1 to 1]. The default
       tone space is TONE = 2*Fd/M. The tone space is the frequency separation
       between successive frequencies.

       Y = MODMAP(X, Fd, Fs, METHOD, M), METHOD = 'fsk', specifies the
       M-ary number M.

       Y = MODMAP(X, Fd, Fs, METHOD, M, TONE), METHOD = 'fsk', specifies the
       tone space TONE, the frequency separation between successive frequency
       in FSK.

       MODMAP(METHOD, M, TONE), METHOD = 'fsk', plots fsk constellation.
       
       The mapped Y can be directly input to COMMOD with METHOD = 'fm' for 
       signal modulation.
fsk_help_end

msk_help_begin
MODMAP Map for minimum shift keying (MSK) modulation.
       Y = MODMAP(X, Fd, Fs, METHOD), METHOD = 'msk', maps a sample frequency
       Fd digital input signal X to a sample frequency Fs output signal Y
       using MSK method. Fs/Fd should be a positive integer. The size of the
       resulting signal Y is Fs/Fd times that of the original signal X. MSK is
       a special case of FSK with M = 2; Tone = Fd. The elements in X must be
       binary numbers.

       Y = MODMAP(METHOD, Fd), METHOD = 'msk', plots MSK constellation.
msk_help_end

samp_help_begin
MODMAP Up sample a signal X form frequency Fd to sample frequency Fs.
       Y = MODMAP(X, Fc, Fd, Fs, METHOD), METHOD = 'sample', takes the input
       signal X with sample frequency Fd (Hz) and outputs signal Y with sample
       frequency Fs (Hz). When X is a matrix, the function takes each column
       as individual signal. The output Y will have the same number of column 
       number as X. Fs must be larger than Fd and Fs/Fd should be an integer.
       When Fd is a two element vector, the second element should be an
       integer which means the offset timing is Fd(2)/Fs. The default offset
       is zero. Fc is not used.
samp_help_end

Wes Wang 10/10/95