diff --git a/boards/Digilent DE0/segmentdisplay.v b/boards/Digilent DE0/segmentdisplay.v
index 4d12f14..3e03c91 100644
--- a/boards/Digilent DE0/segmentdisplay.v	
+++ b/boards/Digilent DE0/segmentdisplay.v	
@@ -1,8 +1,23 @@
-// 7-segment display driver for DE0 board
-//
-// Niels Moseley - Moseley Instruments 2017
+// SPEECH 256
+// Copyright (C) 2017 Niels Moseley / Moseley Instruments
 // http://www.moseleyinstruments.com
 //
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+//
+// 7-segment display driver for DE0 board
+
 
 module segmentdisplay (
     clk,
diff --git a/boards/Digilent DE0/speech256_de0.v b/boards/Digilent DE0/speech256_de0.v
index 022fe67..0838d8e 100644
--- a/boards/Digilent DE0/speech256_de0.v	
+++ b/boards/Digilent DE0/speech256_de0.v	
@@ -1,9 +1,22 @@
+// SPEECH 256
+// Copyright (C) 2017 Niels Moseley / Moseley Instruments
+// http://www.moseleyinstruments.com
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
 // 
 // Speech256 DE0 board top level
 //
-// Niels Moseley - Moseley Instruments 2017
-// http://www.moseleyinstruments.com
-//
 
 //`define USE_SDDAC
 `define YOUTUBE_MESSAGE
diff --git a/verilog/controller/controller.v b/verilog/controller/controller.v
index 9783b07..f71c4ec 100644
--- a/verilog/controller/controller.v
+++ b/verilog/controller/controller.v
@@ -1,10 +1,23 @@
+// SPEECH 256
+// Copyright (C) 2017 Niels Moseley / Moseley Instruments
+// http://www.moseleyinstruments.com
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
 // 
 // Speech256 controller / sequencer
 //
-// Niels Moseley - Moseley Instruments 2017
-// http://www.moseleyinstruments.com
-//
-// 
 
 module CONTROLLER (
         clk,        // global Speech256 clock
diff --git a/verilog/controller/controller_tb.v b/verilog/controller/controller_tb.v
index 2a2c343..95b375f 100644
--- a/verilog/controller/controller_tb.v
+++ b/verilog/controller/controller_tb.v
@@ -1,9 +1,22 @@
+// SPEECH 256
+// Copyright (C) 2017 Niels Moseley / Moseley Instruments
+// http://www.moseleyinstruments.com
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
 // 
 // Controller testbench
 //
-// Niels Moseley - Moseley Instruments 2017
-// http://www.moseleyinstruments.com
-//
 
 module CONTROLLER_TB;
     reg clk, rst_an; 
diff --git a/verilog/controller/xlat.v b/verilog/controller/xlat.v
index 20011b0..2f12485 100644
--- a/verilog/controller/xlat.v
+++ b/verilog/controller/xlat.v
@@ -1,10 +1,24 @@
+// SPEECH 256
+// Copyright (C) 2017 Niels Moseley / Moseley Instruments
+// http://www.moseleyinstruments.com
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
 //
 // 8-bit sign-magnitude to 10-bit sign-magnitude 
 // conversion block
 //
-// Niels Moseley - Moseley Instruments 2017
-// http://www.moseleyinstruments.com
-//
 //
 // C1: x*8
 // C2: 301 + (x-38)*4 = 301 - 152 + x*4 = 149 + x*4
diff --git a/verilog/controller/xlat_tb.v b/verilog/controller/xlat_tb.v
index 6042ad5..b5b07c3 100644
--- a/verilog/controller/xlat_tb.v
+++ b/verilog/controller/xlat_tb.v
@@ -1,9 +1,22 @@
+// SPEECH 256
+// Copyright (C) 2017 Niels Moseley / Moseley Instruments
+// http://www.moseleyinstruments.com
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
 // 
 // XLAT testbench
 //
-// Niels Moseley - Moseley Instruments 2017
-// http://www.moseleyinstruments.com
-//
 
 module XLAT_TB;    
     reg [7:0]  c8_in;
diff --git a/verilog/filter/filter.v b/verilog/filter/filter.v
index 8dced80..55f00fe 100644
--- a/verilog/filter/filter.v
+++ b/verilog/filter/filter.v
@@ -1,10 +1,23 @@
+// SPEECH 256
+// Copyright (C) 2017 Niels Moseley / Moseley Instruments
+// http://www.moseleyinstruments.com
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
 // 
 // 12th order all-pole filter with
 // internal coefficient RAM
 //
-// Niels Moseley - Moseley Instruments 2017
-// http://www.moseleyinstruments.com
-//
 
 module FILTER (
         clk, 
diff --git a/verilog/filter/filter_tb.v b/verilog/filter/filter_tb.v
index 9b872dc..a38893d 100644
--- a/verilog/filter/filter_tb.v
+++ b/verilog/filter/filter_tb.v
@@ -1,9 +1,23 @@
+// SPEECH 256
+// Copyright (C) 2017 Niels Moseley / Moseley Instruments
+// http://www.moseleyinstruments.com
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
 // 
 // FILTER testbench
 //
-// Niels Moseley - Moseley Instruments 2017
-// http://www.moseleyinstruments.com
-//
+
 
 module FILTER_TB;
     reg clk, rst_an, start, coef_load, check_finish, clear_states; 
diff --git a/verilog/pwmdac/pwmdac.v b/verilog/pwmdac/pwmdac.v
index 5d7307e..88bb612 100644
--- a/verilog/pwmdac/pwmdac.v
+++ b/verilog/pwmdac/pwmdac.v
@@ -1,11 +1,24 @@
+// SPEECH 256
+// Copyright (C) 2017 Niels Moseley / Moseley Instruments
+// http://www.moseleyinstruments.com
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
 // 
 // Very simple, i.e. 8-bit non noise-shaping pulse-width modulation (PWM) DAC.
 // The DAC has a pull interface.
 //
-// Niels Moseley - Moseley Instruments 2017
-// http://www.moseleyinstruments.com
-//
-//
 // For a 10 kHz output rate, the clock rate should be 2.560 MHz
 // 
 
diff --git a/verilog/pwmdac/pwmdac_tb.v b/verilog/pwmdac/pwmdac_tb.v
index 60ffe23..a40d56f 100644
--- a/verilog/pwmdac/pwmdac_tb.v
+++ b/verilog/pwmdac/pwmdac_tb.v
@@ -1,9 +1,23 @@
+// SPEECH 256
+// Copyright (C) 2017 Niels Moseley / Moseley Instruments
+// http://www.moseleyinstruments.com
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
 // 
 // PWMDAC testbench
 //
-// Niels Moseley - Moseley Instruments 2017
-// http://www.moseleyinstruments.com
-//
 
 module PWMDAC_TB;
     reg clk, rst_an; 
diff --git a/verilog/sd2dac/sd2dac.v b/verilog/sd2dac/sd2dac.v
index 53da5b0..97c734c 100644
--- a/verilog/sd2dac/sd2dac.v
+++ b/verilog/sd2dac/sd2dac.v
@@ -1,13 +1,26 @@
+// SPEECH 256
+// Copyright (C) 2017 Niels Moseley / Moseley Instruments
+// http://www.moseleyinstruments.com
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
 // 
 // Second-order sigma-delta DAC 
 // The DAC has a pull interface.
 //
 // Number of input bits used: 12
 //
-// Niels Moseley - Moseley Instruments 2017
-// http://www.moseleyinstruments.com
-//
-//
 // Designed for a clock rate of 2.5 MHz
 // 
 
diff --git a/verilog/sd2dac/sd2dac_tb.v b/verilog/sd2dac/sd2dac_tb.v
index 07e5eca..80c50e5 100644
--- a/verilog/sd2dac/sd2dac_tb.v
+++ b/verilog/sd2dac/sd2dac_tb.v
@@ -1,9 +1,23 @@
+// SPEECH 256
+// Copyright (C) 2017 Niels Moseley / Moseley Instruments
+// http://www.moseleyinstruments.com
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
 // 
 // PWMDAC testbench
 //
-// Niels Moseley - Moseley Instruments 2017
-// http://www.moseleyinstruments.com
-//
 
 module SD2DAC_TB;
     reg clk, rst_an; 
diff --git a/verilog/sd2dac/show_tb_results.m b/verilog/sd2dac/show_tb_results.m
index 4b88d18..b8529bf 100644
--- a/verilog/sd2dac/show_tb_results.m
+++ b/verilog/sd2dac/show_tb_results.m
@@ -1,3 +1,21 @@
+%// SPEECH 256
+%// Copyright (C) 2017 Niels Moseley / Moseley Instruments
+%// http://www.moseleyinstruments.com
+%//
+%// This program is free software: you can redistribute it and/or modify
+%// it under the terms of the GNU General Public License as published by
+%// the Free Software Foundation, either version 3 of the License, or
+%// (at your option) any later version.
+%//
+%// This program is distributed in the hope that it will be useful,
+%// but WITHOUT ANY WARRANTY; without even the implied warranty of
+%// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+%// GNU General Public License for more details.
+%//
+%// You should have received a copy of the GNU General Public License
+%// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+%//
+%//
 %
 % Show testbench results for sd2dac
 % 
diff --git a/verilog/source/source.v b/verilog/source/source.v
index 5cdcf80..59b47f4 100644
--- a/verilog/source/source.v
+++ b/verilog/source/source.v
@@ -1,10 +1,22 @@
+// SPEECH 256
+// Copyright (C) 2017 Niels Moseley / Moseley Instruments
+// http://www.moseleyinstruments.com
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
 // 
 // Source part of speech synth
 //
-// Niels Moseley - Moseley Instruments 2017
-// http://www.moseleyinstruments.com
-//
-// 
 
 module SOURCE (
         clk, 
diff --git a/verilog/source/source_tb.v b/verilog/source/source_tb.v
index c00e388..82e78c8 100644
--- a/verilog/source/source_tb.v
+++ b/verilog/source/source_tb.v
@@ -1,9 +1,22 @@
+// SPEECH 256
+// Copyright (C) 2017 Niels Moseley / Moseley Instruments
+// http://www.moseleyinstruments.com
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
 // 
 // PWMDAC testbench
 //
-// Niels Moseley - Moseley Instruments 2017
-// http://www.moseleyinstruments.com
-//
 
 module SOURCE_TB;
     reg clk, rst_an, strobe; 
diff --git a/verilog/speech256_top/speech256_top.v b/verilog/speech256_top/speech256_top.v
index 6413094..0c3ce40 100644
--- a/verilog/speech256_top/speech256_top.v
+++ b/verilog/speech256_top/speech256_top.v
@@ -1,10 +1,22 @@
-// 
-// Speecht256 top level
-//
-// Niels Moseley - Moseley Instruments 2017
+// SPEECH 256
+// Copyright (C) 2017 Niels Moseley / Moseley Instruments
 // http://www.moseleyinstruments.com
 //
-// 
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+// Speech256 top level
+//
 
 module SPEECH256_TOP (
         clk,        // global Speech256 clock (256*10kHz)
diff --git a/verilog/speech256_top/speech256_top_tb.v b/verilog/speech256_top/speech256_top_tb.v
index a8f19a2..8c6c1d8 100644
--- a/verilog/speech256_top/speech256_top_tb.v
+++ b/verilog/speech256_top/speech256_top_tb.v
@@ -1,9 +1,23 @@
-// 
-// PWMDAC testbench
-//
-// Niels Moseley - Moseley Instruments 2017
+// SPEECH 256
+// Copyright (C) 2017 Niels Moseley / Moseley Instruments
 // http://www.moseleyinstruments.com
 //
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+// 
+// Speech256 top level testbench
+//
 
 module SPEECH256_TOP_TB;
     reg clk, rst_an; 
diff --git a/verilog/spmul/spmul.v b/verilog/spmul/spmul.v
index 04b5b62..46f2bbf 100644
--- a/verilog/spmul/spmul.v
+++ b/verilog/spmul/spmul.v
@@ -1,11 +1,22 @@
+// SPEECH 256
+// Copyright (C) 2017 Niels Moseley / Moseley Instruments
+// http://www.moseleyinstruments.com
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
 // 
 // 16bit x 10bit signed serial/parallel multiplier.
 //
-// Niels Moseley - Moseley Instruments 2017
-// http://www.moseleyinstruments.com
-//
-//
-// 
 
 module SPMUL (
         clk, 
diff --git a/verilog/spmul/spmul_tb.v b/verilog/spmul/spmul_tb.v
index 27b96a9..7fc947e 100644
--- a/verilog/spmul/spmul_tb.v
+++ b/verilog/spmul/spmul_tb.v
@@ -1,9 +1,22 @@
+// SPEECH 256
+// Copyright (C) 2017 Niels Moseley / Moseley Instruments
+// http://www.moseleyinstruments.com
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
 // 
 // SPMUL testbench
 //
-// Niels Moseley - Moseley Instruments 2017
-// http://www.moseleyinstruments.com
-//
 
 module SPMUL_TB;
     reg clk, rst_an, start;