generator and a parallel to serial converter the code generator produces a rate 16 18 or 16 17 code the present invention also includes a method that is directed to encoding bit strings and comprises the steps of 1 converting the input strings to input bits and 2 adding at least one bit to produce an encoded string with many ones and a hamming distance greater than one after precoding application_number US 79168797 A description while the present invention will now be described with reference to a communication system encountered in magnetic recording practice those skilled in the art will realize that the present invention can be incorporated into any one of a variety of systems for transmitting binary data referring now to fig1 a preferred embodiment of a communications system 10 constructed in accordance with the present invention is shown the preferred embodiment of the system 10 comprises an encoder 12 a precoder 14 a partial response pr channel 16 a detector 18 and a decoder 20 the pr channel 16 preferably further comprises a low pass filter 40 a noise source 42 and an adder 44 the encoder 12 produces novel many ones codes with hamming distance greater than one the novel many ones codes are particularly advantageous because after precoding the coded sequence output by the channel 16 has at least a predetermined number of ones more specifically the predetermined minimum number of ones at the output of the pr channel 16 contribute to clocking by providing transitions from which frequency and phase information can be extracted the preferred embodiment of the present invention preferably has eleven exemplary.