I'm using 2020 version but, I don't know how to change code from 2015 version

2 lines codes are 2015 version

hmodem =   modem.qammod(0:M-1, M, 'bin', 'UnitAveragePower', true)
all_sym = modulate(hmodem,binary);

some staffs adviced me but, these weren't useful and helpful so, i want to know detail to change methods in 2020 version from 2015 version.

please tell me about 2lines

[Rik]

Generally when a function is removed both the documentation and the release notes will contain advice about alternatives. Where did you search?

[Choi]

Sorry sir, I was mistake upload my codes

original code is hmodem = modem.qammod('M',M, 'SymbolOrder', 'Gray','InputType', 'bit')

and all_sym = modulate(hmodem,binary);

i want to change in 2020version

Answer 1

[Walter Roberson]

The R2020a version of that code is:

error('comm:modem:InvalidUsage', 'Invalid usage. Type ''help modem.qammod'' to see correct usage.')

Details:

The first parameter to modem.qammod can never be a vector: it must be either a scalar (M) or else an existing modem.qammod object, or else a character vector that is part of a name / value pair.

The second parameter to modem.qammod can only be numeric if the first parameter was a numeric scalar (in which case the second parameter can be the phase offset) -- or if the first parameter was a character vector such as 'M'

The 'bin' option can only occur if it is part of a name/value pair and the proceeding option name is 'SymbolOrder'

The option 'UnitAveragePower', true was valid in R2015a -- and is also valid in the current qammod() call.

all_sym = modulate(hmodem,binary);

You can only pass binary to modulate if the modem.qammod object was created with M = 2, or if it was created with 'InputType', 'bit' . Otherwise you need to pass integers to modulate()

For the reasons described above, it is not possible for the call you gave to work, so the R2020a version of the code would have to be to issue the same error message as would have been given in R2015.

[Choi]

Sorry sir, I was mistake upload my codes

original code is

hmodem =   modem.qammod('M',M,  'SymbolOrder', 'Gray','InputType', 'bit') 

and

all_sym = modulate(hmodem,binary);

i want to change in 2020version

[Walter Roberson]

all_sym = qammod(binary, M, 'gray', 'InputType', 'bit');

[Choi]

Thank you sir, then is first code hmodem = qammod('M',M, 'SymbolOrder', 'Gray','InputType', 'bit') ??

[Walter Roberson]

No. There is no modern equivalent for creating a modem.qammod object to be used for later modulation -- at least not using that series of calls. (There are comm.* system objects https://www.mathworks.com/help/comm/ref/comm.rectangularqammodulator-system-object.html but they will be removed soon.)

The code I posted,

all_sym = qammod(binary, M, 'gray', 'InputType', 'bit');

replaces both lines of

hmodem =   modem.qammod('M',M,  'SymbolOrder', 'Gray','InputType', 'bit') ;
all_sym = modulate(hmodem,binary);

[Choi]

Thank you so much.

can i ask my one question?

i changed code lines are these correct? I marked %%%%%%

decimal = 0:M-1;
binary = de2bi(decimal(:),  log2(M)  ,'left-msb')';
% all_sym = modulate(hmodem,binary);
all_sym = qammod(binary, M, 'gray', 'InputType', 'bit');
inactive = [0];
symbol = (1/sqrt(42))*[inactive;all_sym.'];
nn=10000;


for kk = 0:2:24
    kk
    for vv = 1:nn
    bit_T = randi([0 1],Nbits,1);
    x = reshape(bit_T,2*Nobit+Nt,[]);
    ante =  bi2de(x(1:Nt,:).' , 'left-msb') + 1;
    
%     digMod1 = modulate(hmodem,x(Nt+1:Nt+Nobit,:));
%     digMod2 = modulate(hmodem,x(Nt+Nobit+1:Nt+2*Nobit,:));
%%%%%%%%%    
digMod1 = qammod(x(Nt+1:Nt+Nobit,:),M);
    digMod11 = datasample(digMod1,1);
    digMod2 = qammod(x(Nt+Nobit+1:Nt+2*Nobit,:),M);
    digMod22 = datasample(digMod2,1);
    digMod3 = [digMod11;digMod22]; 
%%%%%%%%%%

[Walter Roberson]

No, that is not correct.

digMod1 = qammod(x(Nt+1:Nt+Nobit,:), M, 'gray', 'InputType', 'bit');
    digMod11 = datasample(digMod1,1);
    digMod2 = qammod(x(Nt+Nobit+1:Nt+2*Nobit,:), M, 'gray', 'InputType', 'bit');
    digMod22 = datasample(digMod2,1);
    digMod3 = [digMod11;digMod22]; 

[Choi]

Thank you sir,

this is 2015 version code digMod1 = modulate(hmodem,x(Nt+1:Nt+Nobit,:))

and this code is 2020 versiondigMod1 = qammod(x(Nt+1:Nt+Nobit,:), M, 'gray', 'InputType', 'bit');

i want to extract 1x1 in this code but appear error 'Index in position 1 exceeds array bounds (must not exceed 4) '

[Walter Roberson]

data_to_modulate = x(Nt+1:Nt+Nobit,:);
digMod1 = qammod(data_to_modulate, M, 'gray', 'InputType', 'bit');

splitting the command in this way will make it easier to see whether the problem is in the indexing into x, or if the problem is in internal to qammod()

[Choi]

Thank you sir work well now. Thanks to your answer and something changed.

[Choi]

if i have question, can i tell you??

[Walter Roberson]

You can post new Questions as you need to.

Sometimes I will notice them; sometimes I will not.

[Pavankalyan D S]

hmodem = modem.qammod('M',M, 'SymbolOrder', 'Gray','InputType', 'bit');

hdemodem = modem.qamdemod('M', M,'SymbolOrder','Gray','OutputType','bit');

I change them to qammod, again getting error

[Pavankalyan D S]

the error:

Error in qammod (line 93)

plotConstellation, outputDataType] = validateInputArgs(M, varargin{:});