Digital signal recorder

A digital signal recorder for recording digital information on an information track of a magnetic recording medium, said digital signal recorder comprising:

• an input port for receiving an information word of n bits in parallel;
• means for inserting m additional bits into the n-bit information word so as to form a plurality of n+m bit channel words, the m additional bits in each channel word being set to a unique one of the 2**m possible values of m bits;
• control signal generating means for receiving and analyzing the plurality of channel words in parallel, the control signal generating means including a number of channels at least equal to the number of channel words, each channel arranged for processing a respective one of the channel words and each channel including;
• time division multiplexing means for dividing the corresponding channel word by a predetermined number of bit units so as to form a plurality of channel word segments;
• memory means for storing predetermined spectrum data according to a predetermined track pattern;
• and
• means for analyzing frequency characteristics of the corresponding channel word by using the stored spectrum data to form an error signal;
• a comparison controller for generating a selection control signal corresponding to the channel word having a smallest error signal frequency characteristic on the basis of the analyzed spectrum;
• means for selecting one of the channel words of n+m bits supplied from said encoding means in response to the selection control signal;
• and
• recording means for recording the selected channel word on the information track of the magnetic recording medium, and wherein;
• the memory means includes a predetermined number of memories for each channel, each memory storing predetermined spectrum data corresponding to a selected track pattern,and including spectrum data for the selected track pattern corresponding to all possible values of the channel word segment;
• an address controller is coupled to the memories for generating an address signal to access spectrum data stored in said memories according to said track pattern;
• the means for analyzing frequency characteristics of the corresponding channel word includes a plurality of accumulation circuits for each channel, each accumulation circuit coupled to a corresponding one of the memories for accumulating said spectrum data read out from the corresponding memory responsive to each channel word segment;
• a like plurality of absolute value calculating circuits for each channel, each absolute value calculating circuit coupled to a corresponding one of the accumulation circuits for calculating an absolute value of the accumulated spectrum data;
• an adder circuit in each channel, arranged for summing together all of the said calculated absolute values so as to form the channel error signal;
• and
• wherein the comparison controller provides the selection control signal for selecting the channel word having the smallest signal by comparing the outputs of said adder circuit of each channel, and generates a control signal for presetting the accumulated values of the accumulation circuits in all of the channels other than the selected channel to the value of the accumulation circuit in the selected channel.

A digital signal recorder for converting an information word of n bits into a channel word of n+m bits to record the converted channel word as digital information on an information track of a magnetic record medium, said digital signal recorder comprising:

• an input port for receiving said information word of n bits in parallel;
• encoding means for inserting m bits into said information word of n bits input in parallel to be converted into at least two channel words of n+m bits, and outputting the converted channel words;
• time division multiplexing means for dividing said converted channel words by a bit unit corresponding to a common multiple of the period of the channel word of n+m bits and the period of spectral energy controlled according to a predetermined track pattern, to thereby output the divided each channel word as a divided parallel channel word;
• memory means for each channel, for storing spectrum data of said spectral energy controlled according to said track pattern corresponding to all data capable of being expressed by said divided parallel channel word;
• address control means for controlling an address so that said spectrum data corresponding to the divided parallel channel words of each channel supplied from said time division multiplexing means are read out from said memory means according to said track pattern;
• accumulating means for each channel, for accumulating the spectrum data read out from said memory means by a channel word unit of n+m bits;
• comparison control means for comparing the resultant values of said accumulating means of each channel with one another to generate a selection control signal for selecting the channel word having the desired frequency characteristics on the basis of the compared result and feeding back a control signal for presetting the accumulation value of the unselected accumulating means to the value of the accumulating means of the selected channel, to said accumulation means;
• and
• recording means for selecting one among the plurality of channel words of n+m bits supplied from said encoding means on the basis of said selection control signal and recording the selected channel word on the information track of the magnetic record medium so as to be a serial channel word.

A method of processing digital data in real time for recording on a magnetic medium such that the recorded data exhibits selected frequency characteristic patterns useful in read head tracking during playback, the method comprising the steps of:

• receiving a series of digital information data bytes for recording;
• assembling a plurality of said information bytes so as to form a parallel information word;
• replicating the information word so as to form multiple information words in parallel;
• inserting at least one additional bit into each information word so as to form a channel word;
• setting the additional bits to a different value in each of the channel words, so that each of the channel words has the same number of information bits but also includes a unique combination of the additional bits;
• analyzing the frequency characteristics of each of the channel words in parallel relative to a selected frequency characteristic pattern;
• selecting one of the channel words that most closely exhibits the selected frequency characteristic pattern;
• and
• recording the selected channel word on the magnetic recording medium wherein analyzing the channel words includes dividing the channel word into a plurality of smaller channel word segments, analyzing the channel word segments, and integrating the results over said plurality of channel word segments so as to form an indication of the frequency characteristics of the entire channel word relative to the selected frequency characteristic pattern.