JPS6027092B2 - magnetic head phase detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a phase detector for a magnetic head having a plurality of channels, in which the phase between channels can be easily detected.

This type of method uses a two-phenomenon oscilloscope and detects the phase between channels based on whether the waveforms are the same. Now connect 2 channels of the magnetic head to one input of the oscilloscope, connect 1 channel to the other input to observe the phase, then connect 3 channels instead of 1 or 2 and re-phase. It will be observed. Therefore, the input section of the oscilloscope must be reconnected each time.

Another drawback is that the phase state must be detected from the waveform of the oscilloscope, which is time-consuming. The present invention allows phase detection to be performed easily.
One embodiment will be described below with reference to the drawings. Figure 1 shows an example of a 4-channel head.
, 2, 3, 4 channels CH, ,CH2,CH3,CH
Set it to 4.

In Figure 2, T and ~T4 are CH and ~CH4, respectively.
is a terminal that can be freely connected, and if the terminals of CH and C are connectors, it is configured as a jack.

OSC is a pulse generator, G is a gate through which the output of the pulse generator PSC is passed while the timer TM is operating, AMM is a multiplier, G2 is a contact point R2, R4, R8 and R6 are in the state shown in the figure, CH, This is a relay drive circuit that drives relay R unless ~CH4 is disconnected. In this case, the relay R has contacts R, ~R8, typically R,, R3, R5
, R7 and R2, R4, R6, R8 are turned on, and vice versa during operation. TM is a timer that keeps the power switch S on for a certain period of time when the power switch S is turned on, and TM is a holding switch thereof. COM is a comparator that compares the reference value and the input from the contact R& side, and if the input exceeds the reference value, outputs the corresponding amount. SI is a waveform shaper, CV is a counter, and CO is a counter whose CV is a constant value. It is a relay control circuit that operates based on the output when counting, and the first output operates relay RA, then RB, and finally RC. It also has the function of resetting the counter CV when relays RA to RC operate. ing. RB~RB8, RA,,RC, are the contacts of relays RB, RA, RC, respectively, RR is the display unit, S
S, ~SS2 are phase control switches. Next, the operation of this device will be explained. First, connect each channel CH, ~CH4 of the magnetic head to the terminals T, ~L, and then switch the power switch S.
When turned on, timer M operates and gate G opens.

Therefore, the output of the pulse generator OSC is amplified by the AMM through the gate ◯ and is added to RB. On the other hand, as the timer TM operates, R2, which is the contact point of relay R,
Each channel CH2, CH3, through R4, Ma, R8
Current flows through CH5 and C. By the way, gate G2 is configured so that relay R will not operate if there is any disconnection in each channel CH, to CH4.
If CH, is now disconnected, relay R will not operate,
The operation of the timer TM ends after a certain period of time has elapsed. Although the details will be described later, in this case, it can be seen that the display device RR is defective because it does not operate. If there is an output from gate G2 to operate relay R, R2, R4, R6
, R8 turns off from on, R3, R5, and R7 turn on from off, and the oscillator OSC changes through AMM, R.
The output of is applied to CH2 via switch SS.

At this time, CH3 is coupled to the comparator COM via R3, RB2, RA, , R&. Further, CH, , CH4 are open. Therefore, the pulse applied to CH2 causes C
Since the pulse can be extracted from the C horse adjacent to H2 by electromagnetic induction, it is added to the output force of OM.

If it falls below the reference value of COM, the waveform shaper S
, there is no output. (If the C ratio and CH3 phase are opposite, S
, of course there is no output to . ) On the other hand, the output from the comparator COM is shaped by a waveform shaper SI and counted by a counter CV. If the counter CV is set to output when a certain number of pulses are counted, the counter CV will be reset through the relay control circuit CO, while the relay RA will operate first and the connection to COM will be replaced with the C melon. CH,
Connect. At this time as well, the output of the oscillator OSC is gate G,
．． It continues to be applied to CH2 through AMM, RB, R,, SS, and the output of CH is changed to C instead of CH3.
OM is carried out in the same manner as in the case of CH3. CH2
If the phases of and CH, are in the same phase, when counter CV counts a certain value, relay RB operates and contacts RB, ~RB
3 is successful. As a result, the output of the oscillator SC is RB2
CH4 is added to CH3 through C
A phase comparison is performed between the ratio and CH4. If CH and .about.CH4 are in phase and RC operates within the time period TM, indicator RR is activated by RC, and it can be confirmed that CH and .about.CH4 are in phase. Here, depending on the head, SS, , SS2 may have CH, CH3, CH2, and CH4 in the same phase, and CH, and CH2 may have opposite phases, so this is to accommodate such heads. Although there is only one COM, if CH2 and CH3 are well shielded, the electromagnetic induction from CH2 to CH3 will be smaller, so
Compared to the case of phase detection between peaks H, CH2, CH3 and C, it is necessary to change the reference level of OM in the comparator. As explained above in the embodiment, the phases of CH, CH2, C ratio and CH3, and CH3 and C ratio are detected within the time set by the timer TM, and if it is good, the display is displayed on the display RR. Phase detection can be performed automatically and easily just by looking at the state of RR.

Continuity checks can also be performed within the time set by the timer TM.

Therefore, if the present invention is applied to phase detection, which is one of the various inspections performed by placing the head on a rotating rotary plate and rotating it at fixed angles, it can contribute to streamlining the head inspection process.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a magnetic head, and FIG. 2 is a configuration diagram showing a magnetic head phase detector in an embodiment of the present invention. OSC...0 pulse generator, G,, G2...
...Gate, TM...Timer, COM...
... Comparator, CV ... Counter, CO ... Relay control circuit, R, RA, RB, RC ... Relay. Figure 1 Figure 2

Claims (1)

[Claims] 1. A means for sending a pulse signal for a certain period of time to an arbitrary channel of a magnetic head having a plurality of channels, and a means for inductively extracting the pulse from a channel adjacent to the channel to which the pulse is applied, so that the pulse having a predetermined level or higher is A magnetic head phase detector equipped with means for determining in-phase when a certain number of induced pulses are present, and determining as anti-phase when the induced pulse is below a predetermined level. 2. The magnetic head phase detector according to claim 1, which is provided with means for sending a continuity check signal to each channel and performing a continuity check before sending a pulse signal to an arbitrary channel. Detector.