scramble codes for Bipolar-AMI are detected when a special sequence of invalid bits of transitions are detected. One issue is that it is not always obvious if this invalid sequence was created because of a scramble code or from an actual error. Using BipolarAMI with the HDB3 scramble encoding, write an example bitstream where a scramble code is received in error, where changing a single bit value by one level (i.e. from 0 to + or - to 0 is acceptable, + to - is not a likely error) will cause more than one bit of incorrectly value to be read.