How to i change the SNR to Vector?

I have following code and i want to change SNR=(-20:10:30). How can i do it in following code.

classdef helperModClassTestChannel < matlab.System
  properties   
    SNR = 20;   
    CenterFrequency = 2.4e9
  end
  properties (Nontunable) 
    SampleRate = 1
    PathDelays = 0
    AveragePathGains = 0
    KFactor = 3  
    MaximumDopplerShift = 0
    MaximumClockOffset = 0
  end
  properties(Access = private)
    MultipathChannel
    FrequencyShifter
    TimingShifter
    C % 1+(ppm/1e6)
  end
  methods
    function obj = helperModClassTestChannel(varargin)
      % Support name-value pair arguments when constructing object
      setProperties(obj,nargin,varargin{:})
    end
  end  
  methods(Access = protected)
    function setupImpl(obj)
      obj.MultipathChannel = comm.RicianChannel(...
        'SampleRate', obj.SampleRate, ...
        'PathDelays', obj.PathDelays, ...
        'AveragePathGains', obj.AveragePathGains, ...
        'KFactor', obj.KFactor, ...
        'MaximumDopplerShift', obj.MaximumDopplerShift);
      obj.FrequencyShifter = comm.PhaseFrequencyOffset(...
        'SampleRate', obj.SampleRate);
    end
    function y = stepImpl(obj,x)
      % Add channel impairments
      
      yInt1 = addMultipathFading(obj,x);
      yInt2 = addClockOffset(obj, yInt1);
      y     = addNoise(obj, yInt2);
    end

    function out = addMultipathFading(obj, in)
   
      
      % Get new path gains
      reset(obj.MultipathChannel)
      % Pass input through the new channel
      out = obj.MultipathChannel(in);
    end
    
    function out = addClockOffset(obj, in)
  
      % Determine clock offset factor
      maxOffset = obj.MaximumClockOffset;
      clockOffset = (rand() * 2*maxOffset) - maxOffset;
      obj.C = 1 + clockOffset / 1e6;
      
      % Add frequency offset
      outInt1 = applyFrequencyOffset(obj, in);

      % Add sampling time drift
      out = applyTimingDrift(obj, outInt1);
    end
    
    function out = applyFrequencyOffset(obj, in)
     
      
      obj.FrequencyShifter.FrequencyOffset = ...
        -(obj.C-1)*obj.CenterFrequency;
      out = obj.FrequencyShifter(in);
    end
    
    function out = applyTimingDrift(obj, in)
   
      originalFs = obj.SampleRate;
      x = (0:length(in)-1)' / originalFs;
      newFs = originalFs * obj.C;
      xp = (0:length(in)-1)' / newFs;
      out = interp1(x, in, xp);
    end
    
    function out = addNoise(obj, in)
   
      out = awgn(in,obj.SNR);
    end
    
    function resetImpl(obj)
      reset(obj.MultipathChannel);
      reset(obj.FrequencyShifter);
    end

    function s = infoImpl(obj)
      if isempty(obj.MultipathChannel)
        setupImpl(obj);
      end
      
      % Get channel delay from fading channel object delay
      mpInfo = info(obj.MultipathChannel);
      
      % Calculate maximum frequency offset
      maxClockOffset = obj.MaximumClockOffset;
      maxFreqOffset = (maxClockOffset / 1e6) * obj.CenterFrequency;
      
      % Calculate maximum timing offset
      maxClockOffset = obj.MaximumClockOffset;
      maxSampleRateOffset = (maxClockOffset / 1e6) * obj.SampleRate;
      
      s = struct('ChannelDelay', ...
        mpInfo.ChannelFilterDelay, ...
        'MaximumFrequencyOffset', maxFreqOffset, ...
        'MaximumSampleRateOffset', maxSampleRateOffset);
    end
  end
end

Answer 1

[Wan Ji]

SNR = -20:10:30;
a(numel(SNR)) = helperModClassTestChannel();
for i = 1:1:SNR
a(i).SNR = SNR(i);
end

[Faheem Ur Rehman]

your code gives me following error

Array formation and parentheses-style indexing with objects of class 'helperModClassTestChannel' is not allowed. Use

objects of class 'helperModClassTestChannel' only as scalars or use a cell array.

[Walter Roberson]

SNR = -20:10:30;
for i = 1:1:SNR
    a{i} = helperModClassTestChannel();
    a{i}.SNR = SNR(i);
end