diff --git a/verilog/filter/matlab/calc_filter_test_response.m b/verilog/filter/matlab/calc_filter_test_response.m
new file mode 100644
index 0000000..8b34083
--- /dev/null
+++ b/verilog/filter/matlab/calc_filter_test_response.m
@@ -0,0 +1,68 @@
+%
+% Calculate filter test response
+%
+
+% the 12-pole filter has the following hex values
+% in 10-bit sign-magnitude format:
+%
+%
+% // section 1
+% coef_in     = 10'h3C9;
+% coef_in     = 10'h1E4;
+% 
+% // section 2
+% coef_in     = 10'h2B8;
+% coef_in     = 10'h1CF;
+% 
+% // section 3
+% coef_in     = 10'h238;
+% coef_in     = 10'h080;
+% 
+% // section 4
+% coef_in     = 10'h195;
+% coef_in     = 10'h1BF;
+% 
+% // section 5
+% coef_in     = 10'h135;
+% coef_in     = 10'h1BF;
+% 
+% // section 6
+% coef_in     = 10'h000;
+% coef_in     = 10'h000;
+
+A1 = [1 -2*hex2dec('1C9')/512 hex2dec('1E4')/512];
+A2 = [1 -2*hex2dec('0B8')/512 hex2dec('1CF')/512];
+A3 = [1 -2*hex2dec('038')/512 hex2dec('080')/512];
+A4 = [1 2*hex2dec('195')/512 hex2dec('1BF')/512];
+A5 = [1 2*hex2dec('135')/512 hex2dec('1BF')/512];
+A6 = [1 2*hex2dec('000')/512 hex2dec('000')/512];
+
+A = conv(A1,conv(A2,conv(A3,conv(A4,conv(A5,A6)))));
+figure(1);
+[H,W] = freqz(1,A,4096,10000);
+plot(W,20*log10(abs(H)));
+title('Frequency response of EH allophone');
+xlabel('Frequency (Hz)');
+ylabel('Magnitude (db)');
+grid on;
+
+% get step response to an input of 16
+x = ones(1,32)*16;
+y = filter(1,A,x);
+figure(2);
+plot(y);
+title('Impulse step to [16 16 16 16 16 16 ...]');
+xlabel('Samples');
+ylabel('Output');
+grid on;
+
+state1 = 0;
+state2 = 0;
+in = 16;
+for I=1:10,
+    accu = in-A1(2)*state1-A1(3)*state2;
+    state2 = state1;
+    state1 = accu;
+    fprintf(1,'%f %f %f\n', accu, state1, state2);
+end;
+