Abstract
In this manuscript a simple method is presented for constructing run length limited error control codes from linear binary block codes. The run length limited properties are obtained via addition of a carefully chosen fixed binary vector - a modifier to all codewords without introducing any additional redundancy. Modifier selection is based on a specific property, which can be found in some of the linear binary block codes control matrices. Similar known methods are based on properties of generator matrices. However some codes are specified via control matrices, for example low density parity check codes. The method proposed in this letter could be applied to some of them directly. This is illustrated in this manuscript using example in which a run length limited low density parity check code is obtained from Gallager code.