【正文】 1 % analyze if QAM was donefigure(3), clfif (input_type == 1) amp。 (test_input_type == 1)subplot(221), stem(data_in), title(39。QAM Binary Input Data39。)。subplot(223), stem(QAM_data_out), title(39。QAM Recovered Binary Data39。)elsesubplot(221), plot(data_samples), title(39。QAM Symbol Input Data39。)。subplot(223), plot(QAM_output_samples), title(39。QAM Recovered Symbols39。)。endsubplot(222), plot(QAM_tx_data), title(39。Transmitted QAM39。)。subplot(224), plot(QAM_rx_data), title(39。Received QAM39。)。dig_x_axis = (1:length(QAM_tx_data))/length(QAM_tx_data)。figure(4), clfif channel_on ==1subplot(313)freq_data = abs(fft(QAM_rx_data))。L = length(freq_data)/2。plot(dig_x_axis(1:L), freq_data(1:L))xlabel(39。FFT of Received QAM39。)axis_temp = axis。subplot(311),freq_data = abs(fft(QAM_tx_data))。plot(dig_x_axis(1:L),freq_data(1:L)), axis(axis_temp)title(39。FFT of Transmitted QAM39。)subplot(312)plot(W/(2*pi),mag)ylabel(39。Channel Magnitude Response39。)elsesubplot(212)freq_data = abs(fft(QAM_rx_data))。L = length(freq_data)/2。plot(dig_x_axis(1:L), freq_data(1:L))title(39。FFT of Received QAM39。)axis_temp = axis。subplot(211),freq_data = abs(fft(QAM_tx_data))。plot(dig_x_axis(1:L),freq_data(1:L)), axis(axis_temp)title(39。FFT of Transmitted QAM39。)end% Plots the QAM Received Signal Constellationfigure(5), clf, plot(xxx,yyy,39。ro39。), grid on, axis([ ]), hold on% % Overlay plot of transmitted constellation% x_const = [ ]。% y_const = [ ]。% plot(x_const, y_const, 39。b*39。)% Overlay of constellation boundarysx1 = [2 2]。 x2 = [1 1]。 x3 = [0 0]。 x4 = [1 1]。 x5 = [2 2]。 x6 = [2 2]。y1 = [2 2]。 y2 = [1 1]。 y3 = [0 0]。 y4 = [1 1]。 y5 = [2 2]。 y6 = [2 2]。plot(x1,y6), plot(x2,y6), plot(x3,y6), plot(x4,y6), plot(x5,y6)plot(x6,y1), plot(x6,y2), plot(x6,y3), plot(x6,y4), plot(x6,y5)hold offtitle(39。16QAM Received Signal Constellation and Decision Boundarys39。)binary_err_bits_QAM = 0。for i = 1:length(data_in)err = abs(data_in(i)QAM_data_out(i))。if err 0binary_err_bits_QAM = binary_err_bits_QAM + 1。endendBER_QAM = 100 * binary_err_bits_QAM/data_length。endfigure(6), clfif channel_on == 1subplot(211), plot(W/(2*pi),mag),title(39。Channel Magnitude Response39。)xlabel(39。Digital Frequency39。),ylabel(39。Magnitude in dB39。)subplot(212), plot(W/(2*pi),phase),title(39。Channel Phase Response39。)xlabel(39。Digital Frequency39。),ylabel(39。Phase in Degrees39。)elsetitle(39。Channel is turned off No frequency response to plot39。)end% Compare output to input and count errorsbinary_err_bits_OFDM = 0。for i = 1:length(data_in)err = abs(data_in(i)output(i))。if err 0binary_err_bits_OFDM = binary_err_bits_OFDM +1。endendBER_OFDM = 100 * binary_err_bits_OFDM/data_length。disp(strcat(39。OFDM: BER=39。, num2str(BER_OFDM,3), 39。 %39。))disp(strcat(39。 Number of error bits=39。, num2str(binary_err_bits_OFDM)))if (do_QAM == 1)disp(strcat(39。QAM: BER=39。, num2str(BER_QAM,3), 39。 %39。))disp(strcat(39。 Number of error bits=39。, num2str(binary_err_bits_QAM)))end% Display text file before and after modulationif (input_type == 2) amp。 (file_input_type == 2)original_text_file = char(data_samples39。)if do_QAM ==1edit endedit end% Listen to soundsif (input_type == 2) amp。 (file_input_type == 3)do_again = 39。139。while ( ~(isempty(do_again)) )disp(39。 39。)disp(39。Press any key to hear the original sound39。), %pausesound(data_samples,11025)disp(39。Press any key to hear the sound after OFDM transmission39。), %pausesound(output_samples,11025)if do_QAM == 1disp(39。Press any key to hear the sound after QAM transmission39。), %pausesound(QAM_output_samples,11025)enddo_again = 39。39。do_again = input(39。Enter 1 to hear the sounds again or press Return to end 39。, 39。s39。)。endend