SU1377897A2 - Device for detecting digital data frequency-and-phase-shift signals reproduced from a magnetic medium - Google Patents

Abstract

The invention relates to magn. records The purpose of the invention is to reduce the detection error with an increase in the recording density of information by reducing intersymbol interference. At the inputs of element 12 there are signals from the outputs of flip-flops 14 and 15 and element 5. When these signals coincide, a pulse sequence is formed, a pulse and which counts trigger 10, which generates a synchronization signal strobe on the element 8 an pulse sequence and from her impulses. These pulses trigger the pulse shaper 24, the output signal of which is fed to one input of element 22, and to the other input of which pulses delayed by the element 23 of the delay element 23 of the output of element 12 delays. When these signals coincide, the output of element 22 forms impulses information 1, arriving at the bus 21. 2 Il.

Description

1

with

4j

00 CD

P1

1H

The invention relates to magnetic recording, in particular, to devices for detecting digital information signals manipulated in frequency and phase.

The aim of the invention is to reduce the detection error while increasing the information recording density due to the reduction of intersymbol interference.

FIG. 1 shows a functional diagram of the device; in fig. 2 - time diagrams of his work.

A device for detecting digital information signals controlled in frequency and phase contains serially connected magnetic head 1, amplifier 2, filter 3 and rectifier 4 connected to the corresponding inputs of the first element I 5 through pulse shapers according to extremums 6 and levels 7 signal, and the output of the first element And 5 is connected to one input of the second IW element connected to the output with the information bus 9 and the other input with the output of the first counting trigger 10 and with the synchronization bus 11. Device It also contains the third element I 12, the first, second and third triggers 13, 14 and 15, the pulse generator 16, the pulse counter 17, the decoder 18 and the second counting trigger 19, while the trigger 13 is connected to the clock and information inputs of the drivers respectively 6 and 7 and the output to the input of the trigger installation 14 ,. connected by a synchronizing input with synchronizing inputs of the trigger 10, 15, 19 and with the output of the decoder 18 and the output with the first input of the element I 12, the second input connected to the output of the trigger 15, the information input of which is connected to the output of the trigger 19 connected to the third input element And 12, to the installation input of the counter 17 and to the output of the element 5. The element 12 is connected to the installation input of the trigger 10, and the counter 17 is connected to the input of the generator 16 and the output to the decoder input 18, except Wow, the device contains a quarter-element AND 20, connected by an output to an additional information bus 21 and connected by a first input to the output of trigger 5

,five

0

5 0 5 0 5 Q

Hera 14 and the second input to the output of the fifth element And 22 connected by the first input through a delay element 23 to the output of the element 12 and the second input through the driver 24 pulses to the output of the element 8.

The device is in the process of forming a series of pulse sequences. The signal recorded with a high density, reproduced by the magnetic head 1, after amplifier 2, filter 3 and rectifier 4 (Fig. 2a) is fed to the inputs of the former 6 according to the extremes, which forms the first pulse sequence (Fig. 2b) and the former 7 at fixed levels, which forms the second pulse sequence (Fig. 2c). The first sequence arrives at the trigger input of the trigger 13, and the second at its information input. As a result, deposition pulses are generated at the output of the trigger 13 (Fig. 2d). The first and second sequences also arrive at the inputs of element 5, which, at the time of their coincidence, forms the third pulse sequence (Figure 2d). For each pulse of this sequence, counter 17 starts to zero and begins to count the high frequency generator pulses 16. Generator 16 frequency and coefficient recalculation of the counter 17 is selected so that the output of the decoder 18, which decrypts certain states of the counter 17, forms a fourth pulse sequence - (Fig. 2e), which arrives at the clock the trigger inputs 19 and 15. The trigger 19 is zeroed by each pulse of the third sequence and is switched for each pulse of the fourth sequence (Fig. 2g). The signal from the output of the trigger 19 for each pulse of the fourth sequence is stored on the trigger 15 (Fig. 2h).

At the same time, the impulses falling from the output of the trigger 13 arrive at the installation input of the trigger 14 and zero it. The trigger 14 maintains the zero state at the output until the first pulse of the fourth sequence after the end of the fallout pulse sets a high potential at the output of the trigger 14 (Fig. 2i). Thus, at the inputs of the element And

12 signals from the outputs of the trigger 15 (Fig. 2h), the trigger 14 (Fig. 2i) and the And 5 element (Fig. 2e) are present. When these signals coincide, a pulse sequence is formed (Fig. 2k), the pulses of which zero the counting trigger 10. The trigger 10 switches over each pulse of the fourth sequence and generates a synchronization signal (FIG. 3L) arriving at the bus 11 strobe on the I element. 8, the third pulse sequence and pulses emanating from it, corresponding to the combination of symbols 00 (Fig. 2m). These pulses trigger the pulse shaper 24, the output of which is fed to one of the inputs of the element And 22 (Fig. 2n). Pulses delayed for a period of sync pulses by delay element 23 (Fig. 2o) are sent to the other input of the element 22 from the output of the element 12. When these signals coincide at the output of the element 22, pulses are formed (figure 2p), multiplying them with the deposition pulses (fig 2i) on the element I 20 forms, OO, g

The pulses of information 1 are fed to the bus 21 (Fig. 2p).

Claims (1)

Invention Formula ten 15 20 25 A device for detecting digital information signals manipulated in frequency and phase and reproduced from a magnetic carrier according to the author. St. No. 1195376, characterized in that, in order to reduce the detection error when the information recording density increases, due to the reduction of intersymbol interference, a pulse shaper and a sequentially connected delay element, the fourth And element and the fifth And element connected to the additional output are introduced into it. the information bus and the corresponding input to the output of the second trigger, while the pulse shaper is connected by the input to the output of the second element And and the output to the corresponding input of the fourth element And, and the delay element is connected by the input to the output of the third element I. S if. R . . - -.-.- LJ five S g d . e I I and t I I III III n П П n n ПП nn ППП -Ljl II Ml I I I I 1 I I I I I I I I I I I I I J J-UTJT-TUnJlTlJlJinJlRrU to jl I I I l jnj UTJTjnjTJajTJTjajiJT n-rL I III III Ji II Ml t I I