ademodce.hlp

数字通信第四版原书的例程

amdsb-tc_help_begin
ADEMODCE Amplitude demodulation, double sideband with transmission carrier.
       Z = ADEMODCE(Y, Fs, METHOD), METHOD = 'am' or 'amdsb-tc', demodulates
       the complex envelope of a AM-DSB-TC modulated signal (by using AMODCE)
       with sample frequency Fs (Hz). When Fs is a two element vector, the
       second element specifies the initial phase in the carrier signal 
       modulation. The unit of the initial phase is rad. NUM and DEN are the
       numerator and denominator of the low-pass filter respectively. The
       sample time of the filter is 1/Fs. When NUM is zero, empty, or not
       given, this function uses the default low-pass filter which is 
       [NUM, DEN] = BUTTER(5, Fc*2/Fs). An offset signal OFFSET = abs(min(Z))
       is subtracted before the signal output. No filter is used in the
       demodulation.

       Z = ADEMODCE(Y, Fs, METHOD, OFFSET), METHOD = 'am' or 'amdsb-tc'
       specifies the offset value.

       Z = ADEMODCE(Y, Fs, METHOD, OFFSET, NUM, DEN), METHOD = 'am' or 
       'amdsb-tc' specifies the numerator NUM and denominator DEN of the
       low-pass filter in the demodulation.

       When METHOD = 'am/costas' or 'amdsb-tc/costas', Costas loop will be
       used in the demodulation.
amdsb-tc_help_end

amdsb-sc_help_begin
ADEMODCE Amplitude demodulation, double sideband suppressed carrier.
       Z = ADEMODCE(Y, Fs, METHOD), METHOD = 'amdsb-sc', demodulates the
       complex envelope of a AM-DSB-SC modulated signal (by using AMODCE)
       with sample frequency Fs (Hz). When Fs is a two element vector, the
       second element is the initial phase in the carrier signal.  No filter
       is used in the demodulation.

       Z = ADEMODCE(Y, Fs, METHOD, NUM, DEN), METHOD = 'amdsb-sc' specifies
       the numerator NUM and denominator DEN of the low-pass filter in the
       demodulation.

       When METHOD = 'amdsb-sc/costas', Costas loop will be used in the 
       demodulation.
amdsb-sc_help_end

amssb_help_begin
ADEMODCE Amplitude demodulation, single sideband suppressed carrier.
       Z = ADEMODCE(Y, Fs, METHOD), METHOD = 'amssb', demodulates the complex
       envelope of a AM-SSB modulated signal (by using AMODCE) with sample
       frequency Fs (Hz).  When Fs is a two element vector, the second
       element is the initial phase in the carrier signal.  No filter is
       used in the demodulation.

       Z = ADEMODCE(Y, Fs, METHOD, NUM, DEN), METHOD = 'amssb' specifies the
       numerator NUM and denominator DEN of the low-pass filter in the
       demodulation.
amssb_help_end

qam_help_begin
ADEMODCE Quadrature amplitude demodulation.
       Z = ADEMODCE(Y, Fs, METHOD), METHOD = 'qam', demodulates the complex
       envelope of a QAM modulated signal (by using AMODCE) with sample 
       frequency Fs (Hz). When Fs is a two element vector, the second element
       is the initial phase in the carrier signal. No filter is used in the
       demodulation.

       The output of this function Z is a matrix with its odd column as the
       in-phase and even column as the quadrature component of the demodulated
       signal.

       Z = ADEMODCE(Y, Fs, METHOD, NUM, DEN), METHOD = 'qam' specifies the
       numerator NUM and denominator DEN of the low-pass filter in the
       demodulation.
qam_help_end

fm_help_begin
ADEMODCE Frequency demodulation.
       Z = ADEMODCE(Y, Fs, METHOD), METHOD = 'fm', demodulates the complex
       envelope of a FM modulated signal (by using AMODCE) with sample 
       frequency Fs (Hz). When Fs is a two element vector, the second element
       is the initial phase in the carrier signal. No filter is used in the
       demodulation.

       Z = ADEMODCE(Y, Fs, METHOD, NUM, DEN), METHOD = 'amssb' specifies the
       numerator NUM and denominator DEN of the low-pass filter in the
       demodulation.
fm_help_end

pm_help_begin
ADEMODCE Analog phase demodulation.
       Z = ADEMODCE(Y, Fs, METHOD), METHOD = 'pm', demodulates the complex
       envelope of a PM modulated signal modulated (by using AMODCE) with
       sample frequency Fs (Hz). When Fs is a two element vector, the second
       element is the initial phase in the carrier signal. No filter is used
       in the demodulation.

       Z = ADEMODCE(Y, Fs, METHOD, NUM, DEN), METHOD = 'pm' specifies the
       numerator NUM and denominator DEN of the low-pass filter in the
       demodulation.
pm_help_end

Wes Wang 9/30/95