Converting 8 bits to a byte for amplitude modulation in Java

Question

So I am writing a program in Java that does amplitude demodulation. I am reading in a sine wave value by value and determining whether I have a '1' or a '0'. For now I am saving them as chars, but am open to suggestions. I know the number of samples per bit, so determining the bit is not an issue.

I can't figure out a way to convert every set of 8 bits in to a byte, so I can then decode the final array of bytes using UTF-8. Is there an effective way of doing that?

Byte.parseByte might be useful for you - set the radix to 2. — Zyga, Jan 19 '15 at 10:24
Don't you mean "bits per sample" Having more than one sample per bit is ambitious. — Peter Lawrey, Jan 19 '15 at 10:26
Why not read 8 bits at a time as almost every kind of real device uses 8 bit bytes already. — Peter Lawrey, Jan 19 '15 at 10:27
Peter Lawrey, I did mean bits per sample, although it doesn't matter as you would just get the inverse, which is still a valid value, just less that 1. — user3333414, Jan 19 '15 at 10:29

score 3 · Accepted Answer · answered Jan 19 '15 at 10:26

3

Try this, from the Byte Java API

String myBitString = "10101010";
int radixTwo = 2;
byte myByteValue = Byte.parseByte(myBitString, radixTwo)

Obviously you can add the byte values to a byte[] array and then use a loop afterwards to display / decode them.

answered Jan 19 '15 at 10:26

J Richard Snape

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score 0 · Answer 2 · answered Jan 19 '15 at 10:33

what could be helpful is a conversion method...

public static byte toByte(boolean[] bits){
    assert bits.length == 8;
    int tmp = 0;
    for (int i = 0; i < 8; i ++){
        if(bits[0] ){
            tmp = tmp + (2^i);
        }
    }
    return (byte)(tmp)
}

Converting 8 bits to a byte for amplitude modulation in Java

2 Answers2