SU1026157A1 - Method of determining time position of signal peak for signal reproduced from magnetic medium - Google Patents

Abstract

METHOD FOR DETERMINING TEMPORARY peak positions SIGNALS YUSPROIZVODIMYH from magnetic media, vklyuchanntsy gain of the output data signal of the magnetic head, forming a threshold signal and comparing the amplified information signal with a threshold signal that distinguishes the fact that, in order to increase the accuracy of determining a time position of the peak shape other the threshold signal, equal in amplitude and opposite in sign to the previously formed signal, also forms three auxiliary signals, with this, the amplitudes of these signals are set to be numerically equal to the values of the time intervals between four consecutive. By the coincidence of the amplified information signal with the threshold signals at the first two matches with the threshold levels of opposite polarity, the temporary position of the peak is determined by dividing the signal obtained by multiplying the first (g two auxiliary signals by (L signal, the resulting summing the first and third auxiliary signals, /

Description

The invention relates to the field of computer engineering, in particular, to the technique of magnetic recording, and specifically to methods of reproducing information from a magnetic storage device. There is a known method of reproducing magnetic recording by the method of detection by peaks, which, for determining the position of the peak of the output signal, includes differentiation, amplification and limitation of the signal, as well as detection with a low threshold voltage Jil}. The disadvantage of such a method of reproducing a magnetic recording is the large error in determining the position of the output signal peak caused by a large force, high-frequency noise and noise due to an increase in the frequency response in the high-frequency region during differentiation of the signal. The method that consists of in that the detection of the position of the peak of the output signal includes the formation of supports; a high level of voltage; the transformation of changes in the carrier magnetization Records of changes in the voltage of the signal at the output of the magnetic head; signal amplification, its differentiation, formation of the leading edge of the signal (at the peak value of the amplified signal from the output of the magnetic head) when the differentiated signal coincides with a zero voltage level; of a differentiated signal with a reference voltage level of 2. The disadvantage of this method is the significant error in determining the position of the peak of the output signal caused by a large gain high-frequency noise and noise due to the rise of the frequency response in the high-frequency region when differentiating the amplified signal from the output of the magnetic head. A large error appears as a distortion of the temporal position of the generated signal when the differentiated signal coincides with the steering level of the nag. The purpose of the invention is to increase the accuracy of determining the temporary position of the peak. The goal is achieved by the fact that in the method of determining the temporal position of the peaks of the signals reproduced from the magnetic media, including amplifying the output information signal of the magnetic head, generating one threshold signal and comparing the amplified information signal with the threshold signal, form another threshold signal equal to amplitude and opposite in sign from before (about the izirovannuyu signal, and also form three auxiliary signals, while the amplitudes of these signals set the numerical equal values of the time intervals between the four consecutive matches of the amplified information signal with the threshold signals at the first two matches with threshold levels of opposite polarity, and the temporary position of the peak is determined by dividing the signal obtained by multiplying the first two auxiliary signals by the signal obtained as a result of the summation of the first and third auxiliary signals. Figure 1 shows voltage profiles explaining the proposed method, fig. - one of the variants of the device for the implementation of the method; in FIG. 3 - timing diagrams explaining the operation of the device. In Figure 1, reference numeral 1 denotes /, the time interval between the first and second matches, to which the first signal corresponds; position 2 is the time interval between the second and third matches, corresponding to the second signal; position 3 is the time interval between the third and fourth coincidences corresponding to the third signal; position 4 is the time interval between the second coincidence and the moment of equality of the signal to the peak value corresponding to the fourth signal. The fourth signal corresponds to the peak of the amplified signal of the magnetic head. Indeed, dc follows from the similarity of AoBc and debs. 1 - Cb 4 From the similarity of Dili1I and uetb -Jii hw / (3c, bj.4-.ef Cb w 1 3 A from Fig. 1, it can be seen that 6 2-4, from where -Vт.е. dividing the product of the values of the first and second signals by the sum of the values of the first and third signals. A device for implementing the proposed method comprises magnetic carrier 5, magnetic head b, amplifier 7, block 8 of comparators, block 9 of formers, meter 10 time intervals, block 11 memory, multiplier 12, sumgator 13, dividing unit 14, logical element OR 15, delay line 16, logical unit 17 in I. Block 8 comparators consists of a source of 18 voltage reference levels and two comparators 19 and 20, Block 9 of formers 9 consists of four formers 2124. The meter of 10 time intervals consists of a high-frequency generator 25, a logical element OR 26 of the counter 27 The memory unit consists of the logical element OR 28 and memory cells 29-31. The device is connected in series with the magnetic head 6, the amplifier 7, the output of which is connected to the first inputs of the comparators 19 and 20, the second inputs of which are connected to the positive and negative outputs atelnogo of levels of a source 18 of reference levels, respectively. The output of the comparator 19 is connected to the inputs of the formers 21 and 22, and the output of the comparator 20 is connected to the inputs of the formers 23 and 24. The output of the imager 21 is connected to the first inputs of the logic elements OR 26, 28. The output of the imager 22 is connected to the second input of the logic element OR 26, addressable the input of the memory cell 31 and the first input of the logic element OR 15. The output of the imaging unit 23 is connected to the third input of the logic element OR 26, the address input of the cell is 30pam and the second input of the logic element ILG 15. The output of the imaging unit 24 is connected to the fourth input of the OR 26 and the second input of the OR 28, the output of which is connected to the address input of the memory cell 29. The output of the logic element OR 26 is connected to the reset input of the counter 27, to the counting input of which the generator output is connected to 25 clock pulses. You move the counter 27 is connected to the information inputs of the memory cells 29-31. The output of the memory cell 29 is connected to the first input of the multiplier 13, the output of which is connected to the input of the divisible dividing unit 14. The output of cell 30 is connected to the second inputs of adder 12 and multiplier} 3, the output of cell 31 has been connected to the first input of adder 14, which is connected to the input of the divider of dividing unit 14, the output of which is connected to the first output of unit 17 of logic elements I, output; logical element OR 15 is connected to the input line 16 ederzhki, the output of which is connected to the second input unit 17 of the logic elements. The output of the logic element unit 17 is the output of the device. The magnetization variations of the carrier 5 records are converted into variations in the voltage of the magnetic signal. These signals are amplified by the amplifier 7. Cocktail 19 produces a signal Lf.C A), obtained by comparing the amplified signal from amplifier 7 with a positive level of Source 18 of the reference Nyrc. The compass & 20 produces a signal from FIG. 3 V j is obtained by comparing the amplified signal from amplifier 7 with a negative level of source 18 of the reference voltage. The shaper 22 generates a short pulse (fig.C C Hpo front edge of the signal from the output of the comparator 19, and the shaper 21 - on the rear (fig.ZE). Shaper 23 forms a short pulse (fig.ZT)) on the leading edge of the signal from the comparator output 20, and the shaper 24 on the rear (fig.ZR). clock pulses from the generator 25, the frequency of which significantly exceeds the frequency of the amplified signal, arrive at the counting input of the counter 27. The pulses from the output of the block of 9 drivers through the logical element OR 26 (figure 3 (3) arrive at the reset input of the counter 27. The counter 27 counts signals between two adjacent reset pulses. Information from the output of the counter 27 (conventionally shown in Fig. 3n) enters one of the memory cells 29-31, after which the state is set to the zero position, ready For a new count, with a group of signals anosit in memory cell 29, if signals from shaper 21 and 24 are received from shaper 21 and 24, in memory cell 30 if from shaper 23, in memory cell 31 - from shaper 22. Groups of signals from cells 29 and 30 the memory is fed to the multiplier 12, where their values are multiplied, and the values of the group of signals received from / cells 30 and 31 of the memory are summed in the adder 13. The divider 14 divides the values of the group of signals from the output of the multiplier by the groups of signals from the output of the adder . From the dividing unit, the group of signals goes to the first group of outputs of the logical unit 17 And the second group of inputs through the logical element OR 15 and the delay line 16 receives signals from the output of drivers 22 and 23. Signals from the output of the delay line 16 (FIG. 3K a) at the output of the block 17 logical elements And produce output corresponding to the peak of the signal of the magnetic head 6. Generating signals at the moment of coincidence of the amplified signal with the reference levels, rather than zero, will significantly improve the accuracy measured The position of the peak of the output signal is eliminated by eliminating the zero drift, and also by eliminating the signal differentiation operation, which distorts the signal by increasing the high-frequency noise and noise.

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Claims (1)

METHOD FOR DETERMINING THE TIME POSITION OF SIGNAL PEAKS PLAYABLE FROM A MAGNETIC CARRIER, including amplification of the output information signal of the magnetic head, generation of one threshold signal and comparison of the amplified information signal with the threshold signal. in order to increase the accuracy of determining the temporal position of the peak, another threshold signal is formed that is equal in amplitude and opposite in sign to the previously generated signal, and three auxiliary signals are generated, and the amplitudes of these signals are set numerically equal to the values of time intervals between four consecutive ones. coincidences of the amplified information signal with threshold signals during the first two matches with threshold * levels of opposite polarity, and the temporal position of the peak is determined by dividing the signal _& obtained by multiplying the first $ two auxiliary signals by the signal obtained by summing the first and third auxiliary . 1026157