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comparison m-toolbox/classes/@ao/heterodyne.m @ 0:f0afece42f48

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Import.
author Daniele Nicolodi <nicolodi@science.unitn.it>
date Wed, 23 Nov 2011 19:22:13 +0100
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1 % HETERODYNE heterodynes time-series.
2 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3 %
4 % DESCRIPTION: HETERODYNE heterodynes time-series.
5 %
6 % The input signal is mixed down at the specified frequency. The mixed
7 % signal is then (optionally) low-pass filtered and (optionally) downsampled
8 % to have the specified bandwidth.
9 %
10 % CALL: b = heterodyne(a,pl)
11 %
12 % INPUTS: pl - a parameter list
13 % a - input analysis object
14 %
15 % OUTPUTS: b - output analysis object containing the filtered data.
16 %
17 % <a href="matlab:utils.helper.displayMethodInfo('ao', 'heterodyne')">Parameters Description</a>
18 %
19 % VERSION: $Id: heterodyne.m,v 1.22 2011/04/08 08:56:16 hewitson Exp $
20 %
21 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
22
23 function varargout = heterodyne(varargin)
24
25 % Check if this is a call for parameters
26 if utils.helper.isinfocall(varargin{:})
27 varargout{1} = getInfo(varargin{3});
28 return
29 end
30
31 import utils.const.*
32 utils.helper.msg(msg.PROC3, 'running %s/%s', mfilename('class'), mfilename);
33
34 % Collect input variable names
35 in_names = cell(size(varargin));
36 for ii = 1:nargin,in_names{ii} = inputname(ii);end
37
38 % Collect all AOs and plists
39 [as, ao_invars] = utils.helper.collect_objects(varargin(:), 'ao', in_names);
40 [pl, pl_invars] = utils.helper.collect_objects(varargin(:), 'plist', in_names);
41
42 % Make copies or handles to inputs
43 bs = copy(as, nargout);
44
45 % Combine plists
46 pl = parse(pl, getDefaultPlist());
47
48
49 % Get parameters
50 t0 = find(pl, 't0');
51 f0 = find(pl, 'f0');
52 if isempty(f0)
53 error('### Please specify the heterodyne frequency with the paramter ''f0''');
54 end
55 mix = find(pl, 'quad');
56
57 for jj = 1:numel(bs)
58 if isa(bs(jj).data, 'tsdata')
59
60 % store input history
61 inhist = bs(jj).hist;
62
63 % check bandwidth
64 bw = find(pl, 'bw');
65 if isempty(bw)
66 bw = bs(jj).data.fs;
67 end
68 if bw > bs(jj).data.fs
69 error('### The output bandwidth can not exceed the input bandwidth');
70 end
71
72 % mix at f0
73 switch lower(mix)
74 case 'cos'
75 bs(jj).data.setY(bs(jj).data.getY .* 2.0 .* cos(2*pi * f0 .* (bs(jj).data.getX - t0)));
76 case 'sin'
77 bs(jj).data.setY(bs(jj).data.getY .* 2.0 .* sin(2*pi * f0 .* (bs(jj).data.getX - t0)));
78 otherwise
79 error('### Unknown quadrature specified');
80 end
81
82
83 % user-input filter for low pass
84 filt = find(pl, 'filter');
85
86 % lowpass filter at bw/w
87 if ~isempty(filt) || utils.prog.yes2true(find(pl, 'lp'))
88 if isempty(filt)
89 % standard filter for low-pass
90 filt = miir(plist('type', 'lowpass', 'order', 4, 'fc', 0.4*bw, 'fs', bs(jj).data.fs));
91 end
92 bs.filtfilt(filt);
93 end
94
95 % downsample
96 if utils.prog.yes2true(find(pl, 'ds'))
97 factor = ceil(bs(jj).data.fs / bw);
98 bs.downsample(plist('factor', factor));
99 end
100
101 % set name and history
102 bs(jj).name = sprintf('heterodyne(%s, %s@%.01f Hz)', ao_invars{jj}, mix, f0);
103 bs(jj).addHistory(getInfo('None'), pl, ao_invars(jj), inhist);
104 % clear errors
105 bs(jj).clearErrors;
106
107 else
108 error('### heterodyne only works on time-series AOs currently.');
109 end
110 end
111
112 % Set output
113 if nargout == numel(bs)
114 % List of outputs
115 for ii = 1:numel(bs)
116 varargout{ii} = bs(ii);
117 end
118 else
119 % Single output
120 varargout{1} = bs;
121 end
122 end
123
124 %--------------------------------------------------------------------------
125 % Get Info Object
126 %--------------------------------------------------------------------------
127 function ii = getInfo(varargin)
128 if nargin == 1 && strcmpi(varargin{1}, 'None')
129 sets = {};
130 pls = [];
131 else
132 sets = {'Default'};
133 pls = getDefaultPlist;
134 end
135 % Build info object
136 ii = minfo(mfilename, 'ao', 'ltpda', utils.const.categories.sigproc, '$Id: heterodyne.m,v 1.22 2011/04/08 08:56:16 hewitson Exp $', sets, pls);
137 ii.setModifier(false);
138 end
139
140 %--------------------------------------------------------------------------
141 % Get Default Plist
142 %--------------------------------------------------------------------------
143 function plout = getDefaultPlist()
144 persistent pl;
145 if exist('pl', 'var')==0 || isempty(pl)
146 pl = buildplist();
147 end
148 plout = pl;
149 end
150
151 function pl = buildplist()
152
153 pl = plist();
154
155 % f0
156 p = param({'f0', 'The heterodyne frequency in Hz.'}, paramValue.EMPTY_DOUBLE);
157 pl.append(p);
158
159 % t0
160 p = param({'t0', 'Modulation start time offset in s.'}, paramValue.DOUBLE_VALUE(0));
161 pl.append(p);
162
163 % quad
164 p = param({'quad', 'The quadrature to output. ''sin'' or ''cos''.'},{2, {'sin', 'cos'}, paramValue.SINGLE});
165 pl.append(p);
166
167 % bw
168 p = param({'bw', 'The bandwidth at the output in Hz.'}, paramValue.EMPTY_DOUBLE);
169 pl.append(p);
170
171 % lp
172 p = param({'lp', 'Low pass filter the output data at ''bw''.'}, paramValue.YES_NO);
173 pl.append(p);
174
175 % filter
176 p = param({'filter', ['Filter to be used to low pass the output data.<br>' ...
177 'If this parameter is set, the low pass is applied regardless to the value of the ''lp'' parameter']}, paramValue.EMPTY_DOUBLE);
178 pl.append(p);
179
180 % ds
181 p = param({'ds','Downsample the output data.'}, paramValue.YES_NO);
182 pl.append(p);
183 end