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From: Rick T on 9 Feb 2010 16:47
Sorry if this got posted twice gremlins started playing with my
computers.

Greetings All

I'm trying to use a slider to adjust the frequency of an audio signal
that is played out my audio card in "realtime" using matlab. I keep
getting an error reference to non-existent field 'freq'.
this is the line of code it saying has the error
set(handles.freq,'Value',sliderValue);

The thing is I created the freq variable right above it. Any
suggestions/ should I be doing it this way?

example code below:

function slider1_Callback(hObject, eventdata, handles)

sliderValue = get(handles.slider1,'Value');
%puts the slider value into the edit text component
set(handles.sliderValue_editText,'String', num2str(sliderValue));

freq=1;
set(handles.freq,'Value',sliderValue); %sets freq when slider changes
%-------error it refers too above

% Update handles structure
guidata(hObject, handles);

function sliderValue_editText_Callback(hObject, eventdata, handles)

sliderValue = get(handles.sliderValue_editText,'String');
%convert from string to number if possible, otherwise returns empty
sliderValue = str2num(sliderValue);

%if user inputs something is not a number, or if the input is less
than 0
%or greater than 100, then the slider value defaults to 0
if (isempty(sliderValue) || sliderValue < 0 || sliderValue > 300)
set(handles.slider1,'Value',0);
set(handles.freq,'Value',1); %sets freq when slider changes
set(handles.sliderValue_editText,'String','0');
else
set(handles.slider1,'Value',sliderValue);
set(handles.freq,'Value',sliderValue); %sets freq when slider
changes
end


function freq_Callback(hObject, eventdata, handles)
ao=analogoutput('winsound');
ao.samplerate=44100;
y = sin(freq*(0:(2*pi/44100):2*pi))'; % creates test signal from freq
variable

chan=addchannel(ao,1:2);
ao.RepeatOutput = 3; % to output 3 times you need to repeat 3 USE
RepeatOutput
putdata(ao,[y y])
start(ao)

% Don't forget to cleanup when done
clear ao
%delete(ao)
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