JP3254767B2 - Recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus suitable for application to a recording apparatus such as a VTR for recording video and audio on a recording medium such as a magnetic tape through a rotary transformer.

[0002]

2. Description of the Related Art Conventionally, for example, a VT for recording video and audio on a recording medium such as a magnetic tape via a rotary transformer.
As a recording device for R or the like, for example, the one shown in FIG. 6 is known.

The recording apparatus shown in FIG. 6 supplies a clock signal generated by a clock generation circuit 1 to an amplification circuit 8 and an exclusive OR circuit 3, respectively, and the exclusive OR circuit 3 should record from the recording system 2. An exclusive OR operation of a video signal, an audio signal, etc., and a clock signal is performed, and this operation output (modulation output) is supplied to an amplifier circuit 4.
The operation output amplified by the amplifier circuit 4 and the output amplified by the amplifier circuit 8 are respectively converted to the rotary transformer 5 and the amplifier circuit 6,
In addition, the exclusive OR circuit 7 supplies the result to the exclusive OR circuit 7 via the rotary transformer 9 and the amplifier circuit 10, performs an exclusive OR operation in the exclusive OR circuit 7, and outputs the operation output (demodulated output) to the amplifier circuit 11 as a current driver. After amplification, it is supplied to a head 12, and the magnetic head 12 records the magnetic tape 13 so as to form an inclined track.

FIG. 5 shows a state of a signal in the recording apparatus, and will be described below with reference to FIG.
5A is supplied from the recording system 2 to the exclusive OR circuit 3, and a clock signal as shown in FIG. 5B is supplied to the exclusive OR circuit 3.
And supplied to the amplifier circuit 8.

[0005] The exclusive OR circuit 3
When the exclusive OR operation, that is, the modulation process, is performed in step (c), the output of the exclusive OR circuit 3 becomes
The output is as shown in

This output (FIG. 5C) is supplied to an exclusive OR circuit 7 through a rotary transformer 5 and an amplifier circuit 6, and a clock signal output from the amplifier circuit 8 is similarly output from the rotary transformer 9 and the amplifier circuit 10.
5D, and is supplied to the exclusive OR circuit 7.

[0007] The exclusive OR circuit 7
, An exclusive OR operation, that is, a demodulation process is performed. As a result, a signal output from the exclusive OR circuit 7 is demodulated into an original signal shown in FIG. 5A as shown in FIG. 5E, and thereafter, As described above, the current driver 1
After the current is amplified by 1, the data is recorded on the magnetic tape 13 by the head 12.

That is, in the above-described method, the exclusive OR circuit 3 performs an exclusive OR operation with the clock signal before inputting the recording data to the rotary transformer 5, thereby performing a phase modulation process, thereby forming a frequency distribution. The DC signal is allowed to pass through the rotary transformer 5 without being affected by the low-frequency cutoff by being concentrated in the middle and high ranges.

[0009]

In the above-described recording apparatus, in order to prevent the signal to be recorded from being affected by the low-frequency cutoff in the rotary transformer 5, in other words, the signal to be recorded is simply a signal to be recorded. Must be provided with two exclusive OR circuits as a modulator and a demodulator in order to allow the signal to pass through a rotary transformer.

Further, since a circuit system for generating a clock signal for modulation and demodulation is required, and a clock signal is required for demodulation, as is apparent from FIG. And 10 and a rotary transformer 9 are required.

That is, in the above-described recording apparatus, an extra channel for the clock signal is required in addition to the channel for the signal to be recorded, so that the circuit scale becomes very large. When the circuit scale is large, power consumption becomes large, and it becomes difficult to realize high-speed transmission and multi-channel transmission, and the price of equipment becomes extremely high. was there.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and reduces power consumption by reducing channels other than channels of signals to be recorded to reduce the circuit scale.
It is an object of the present invention to propose a recording apparatus which can be reduced in price and can cope with high-speed transmission and multi-channel.

[0013]

According to the present invention, there is provided a signal processing means for processing an information signal to be recorded;
Rotary transformers 15 and 21 for transmitting the recording signal from the signal processing means to the head 12 side, and an output signal having a low-frequency cutoff by passing through the rotary transformers 15 and 21 and having a differentiated waveform of the original signal. A waveform shaping means 16 for detecting the rising and falling edges and applying a positive feedback to maintain the high level and the low level to restore the original signal, and record the output from the waveform shaping means 16 on the recording medium 13. Recording means 25, 12
And a recording apparatus characterized by having the following.

[0014]

[0015]

According to a second aspect of the present invention, in the first aspect, a rotary transformer 1 is provided before the waveform shaping means 16.
The recording apparatus is provided with level shift means R2, R3, and 22 for shifting the output levels from the outputs 5 and 21.

According to a third aspect of the present invention, in the first or second aspect, the waveform shaping means 16 compares the outputs of the rotary transformers 15 and 21 with the comparing means R4, R5, R
8, R9, 23 and R23, R24, R25, R26,
26, wherein the comparison operation has a hysteresis characteristic.

The present invention according to claim 4 is the invention according to claim 3, wherein the comparing means R4, R5, R8, R9, 23 and R2
3, R24, R25, R26, 26 are operational amplifiers 23
And 26 have first input terminals connected to first resistors R4 and R23.
, And second resistors R5 and R24 are connected to the other input terminals of the operational amplification means 23 and 26, respectively. One input terminal and the first output terminal of the operational amplification means 23 and 26 are connected to the third output terminal. And the other input terminal and the second output terminal of the operational amplifier means 23 and 26 are connected to the fourth
And a resistor R9 and a resistor R26.

The present invention according to claim 5 is the invention according to claim 4, wherein the first resistor R4, R23 and the third resistor R8, R
The comparison means R4, R5, R8, R
9, 23, and R23, R24, R25, R26, 26 to control the hysteresis characteristics.

According to a sixth aspect of the present invention, in any one of the third to fifth aspects of the present invention, there is provided a DC cut-off circuit disposed between the rotary transformers 15, 21 and the waveform shaping means 16. , And comparing means R4, R5, R8, R provided in the waveform shaping means 16.
9, 23 and R23, R24, R25, R26, 26, the output level from the rotary transformer 12, 21 is compared with the comparing means R4, R5, R8, R9, 23 and R23, R2.
4. A recording apparatus comprising recording means 25 and 12 for recording the output from the waveform shaping means 16 on a recording medium 13 when the hysteresis is larger than R25, R26 and 26.

[0021]

According to the configuration of the present invention according to claim 1,
The waveform shaping means 16 detects the rising and falling edges of the output signal which has undergone the low-frequency cutoff by passing through the rotary transformers 15 and 21 and has become a differentiated waveform of the original signal, and provides a high level by applying positive feedback. , Maintain the low level and restore the original signal.

[0023]

According to the configuration of the present invention according to claim 2,
Comparing means R4, R5, R8, R9, 23 and R23, R
24, R25, R26, 26, the rotary transformer 1 is provided by level shift means R2, R3, 22 provided in the preceding stage.
The level of the output from 5, 21 is shifted.

According to the configuration of the present invention according to claim 3,
Comparing means R4, R5, R8, R9, 23 and R23, R
At 24, R25, R26, and 26, a comparison operation is performed with a hysteresis characteristic.

According to the configuration of the present invention according to claim 4,
The first resistors R4 and R23 are connected to one input terminals of the operational amplifiers 23 and 26, and the second resistors R5 and R24 are connected to the other input terminals of the operational amplifiers 23 and 26. One input terminal and the first output terminal of the operational amplifier means 23 and 26 are connected by third resistors R8 and R25, and the other input terminal and the second output terminal of the operational amplifier means 23 and 26 are connected to the second output terminal. And R4, R5, R8, R9, 23 and R which are connected by four resistors R9 and R26.
23, R24, R25, R26, 26 perform a comparison operation.

According to the configuration of the present invention according to claim 5,
First resistor R4, R23 and third resistor R8, R2
The comparison means R4, R5, R8, R
9, 23 and the hysteresis of the comparison operation of R23, R24, R25, R26, 26 is controlled.

According to the configuration of the present invention, the DC component is cut by the capacitors C1 and C2 disposed between the rotary transformers 15 and 21 and the waveform shaping means 16.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the recording apparatus of the present invention will be described below in detail with reference to FIG.

In FIG. 1, portions corresponding to those in FIG. 6 are denoted by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 1, video and audio signals output from a recording system 2 such as a helical scan type tape recorder are supplied to a waveform shaping circuit 16 via a rotary transformer 15. The waveform shaping circuit 16 detects the rising and falling edges of a signal that has become a differential waveform of the original signal (low-frequency component) due to the influence of the low-frequency cutoff from the rotary transformer 15, and simultaneously performs positive feedback to perform high and low Maintain the low level and restore the original signal.

The original signal restored by the waveform shaping circuit 16 is supplied to the head 12 and recorded on the magnetic tape 13 by the head 12 so as to form an inclined track.

That is, as shown in FIG. 2, the original signal (see FIG. 2A) output from the recording system 2 is affected by low-frequency cutoff when passing through the rotary transformer 15 as shown in FIG. 2B. A differential waveform corresponding to the rising and falling edges of the original signal is obtained. Since the waveform shaping circuit 16 detects the rising edge and the falling edge of this differentiated waveform and performs positive feedback at the same time, as shown in FIG. 2
The same signal as the original signal shown in A can be restored.

Next, a specific example 1 of the recording apparatus shown in FIG. 1 will be described with reference to FIG.

In FIG. 3, reference numeral 20 denotes an input terminal to which a video or audio signal to be recorded is supplied from a helical scan type tape recorder main body (not shown) or from the outside, and is supplied through the input terminal 20. The signal to be recorded is supplied to a recording system 2 where various processing for recording is performed.

The signal processed and output by the recording system 2 is supplied to the primary side of the rotary transformer 21.

Here, the rotary transformer 21
To explain the connection on the secondary side, in the circuit shown in FIG. 3, one end of the secondary side of the rotary transformer 21 is connected to the inverting input terminal of the operational amplifier circuit 22, and this inverting input terminal is operated via the resistor R3. The other end of the secondary side of the rotary transformer 21 is connected to a non-inverting input terminal of the operational amplifying circuit 22. This non-inverting input terminal is connected to a resistor via a resistor R2. R3 is connected to a connection point between the internal reference voltage terminal of the operational amplifier circuit 22 and a resistor R1 is connected between the inverted and non-inverted input terminals of the operational amplifier circuit 22.
The inverting output terminal of the operational amplifier circuit 22 is connected to the inverting input terminal of the operational amplifier circuit 23 via a resistor R4, and the non-inverting output terminal of the operational amplifier circuit 22 is operated via a resistor R5. It is connected to the non-inverting input terminal of the circuit 23, the inverting input terminal and the inverting output terminal of the operational amplifier circuit 23 are connected by a resistor R8, and the non-inverting input terminal and the non-inverting output terminal of the operational amplifier circuit 23 are connected by a resistor. A non-inverting output terminal of the operational amplifier circuit 22 and a power supply terminal 24 to which a voltage of, for example, minus 5 V is supplied are connected via a resistor R6. Connected to the power supply terminal 24 via the circuit R7,
3 is connected to the power supply terminal 24 via the resistor R11.
, And the non-inverting output terminal of the operational amplifier circuit 23 is connected to the power supply terminal 24 via the resistor R10.
3 inverting and non-inverting output terminals are connected to the head driver 25, respectively.
And the output end of the head driver 25 is connected to the head 12.

Here, the resistor R1 is for flowing an extra current through the circuit, the resistors R2 and R3 are for biasing, for example, for emitter coupled logic (ECL), and the resistors R6 and R7 are for ECL. The output pull-down resistor and the operational amplifier 22 are so-called level shifters for shifting the level, and the output of the operational amplifier 22 is ECL.
Output.

A comparator is composed of the resistors R4, R5, R8, R9 and the operational amplifier circuit 23.
By adjusting the ratio of the resistance values of R5 and R8 and the ratio of the resistance values of R5 and R9, the hysteresis characteristic of this comparator can be varied. This operational amplifier circuit 23 attempts to maintain the threshold level when it exceeds the threshold level.

Here, the voltage by the internal reference voltage terminal of the operational amplifier circuit 22 is Vbb, and the high level of the ECL level is V.
h, the low level is Vl, and the resistance value r4 of the resistors R4 and R5
And r5 are equal, and the resistance values r8 and r9 of the resistors R8 and R9
Are equal, the threshold level Vt
(H) and Vt (L) can be expressed by Equations 1 and 2 below.

[0041]

Vt (H) = (Vbb−V1) × r4 / r8 +
Vbb = (Vbb−V1) × r5 / r9 + Vbb

[0042]

Vt (L) = (Vbb−Vh) × r4 / r8 +
Vbb = (Vbb−Vh) × r5 / r9 + Vbb

Next, the operation of the circuit shown in FIG. 3 will be described. The original signal output from the recording system 2 has a differential waveform as shown in FIG. 2B due to the influence of low-frequency cutoff when passing through the rotary transformer 21.

The output having this differentiated waveform is level-shifted by the operational amplifier circuit 22 and then output from the operational amplifier circuit 23.
Supplied to The operational amplifier circuit 23 detects the rise and fall of the input signal waveform shown in FIG. 2B, and further applies positive feedback to raise the level of the differential waveform.
In any of the falling cases, when the voltage is equal to or higher than the threshold, an operation of maintaining the level is performed.
As shown in C, the same signal as the original signal is obtained.

The signal restored to the same signal as the original signal is subjected to current amplification in the head driver 25 and then the head 12
Is recorded on the magnetic tape 13 by the head 12 so as to form an inclined track.

As described above, in this example, the level of the original signal that has become a differentiated waveform due to the influence of the low-frequency cutoff in the rotary transformer 21 is level-shifted by the operational amplifier circuit 22, and furthermore, it is converted by the operational amplifier circuit 23 as the original signal. Since the data is restored, the number of channels other than the channel of the signal to be recorded, such as a clock signal, is reduced to reduce the circuit size, thereby achieving low power consumption and low cost. , High-speed transmission and multi-channel operation.

Next, a specific example 2 of the recording apparatus shown in FIG. 1 will be described with reference to FIG.

In FIG. 4, portions corresponding to those in FIG. 3 are denoted by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 4, reference numeral 20 denotes an input terminal to which a video or audio signal to be recorded is supplied from a helical scan type tape recorder main body (not shown) or from the outside. The signal to be recorded is supplied to a recording system 2 where various processes for recording are performed.

The signal processed and output by the recording system 2 is supplied to the primary side of the rotary transformer 21.

Here, the rotary transformer 21
The connection shown on the secondary side will be described. The circuit shown in FIG.
20, one end of the rotary transformer 21 on the secondary side is connected to the inverting input terminal of the operational amplifier circuit 26 via the capacitor C1 and the resistor R23, and the inverting input terminal is connected to the operational amplifier via the resistor R25. The inverting output terminal of the circuit 26 is connected, the connection point of the capacitor C1 and the resistor R23 is connected to the internal reference voltage terminal of the operational amplifier circuit 26 via the resistor R22, and the other end of the rotary transformer 21 on the secondary side is connected. The non-inverting input terminal of the operational amplifier circuit 22 is connected to the non-inverting input terminal of the operational amplifier circuit 22 via the capacitor C2 and the resistor 24. The non-inverting input terminal is connected to the non-inverting output terminal of the operational amplifier circuit 26 via the resistor R26. And a connection point of the resistor R24 and a connection point of the resistor R22 and the internal reference voltage terminal of the operational amplifier circuit 26 via the resistor R21. The non-inverting output terminal and a resistor between the power supply terminal 24 a voltage of minus 5V is supplied for example R27
The inverting output terminal of the operational amplifier circuit 26 is connected to the power supply terminal 24 via the resistor R28, and the inverting and non-inverting output terminals of the operational amplifier circuit 26 are connected to the head driver 25, respectively. The output terminals of the driver 25 are connected to the head 12, respectively.

Here, the resistor R20 is for passing an excess current to the circuit, the capacitors C1 and C2 are for DC cut, the resistors R21 and R22 are for bias, and the resistors 23, R25, R24, R26 and Operational amplifier circuit 26
The hysteresis characteristic of the comparator can be varied by adjusting the ratio of the resistances r23 and r25 of the low-resistance devices R23 and R25 and the resistances r24 and r26 of the resistors R24 and R26. This operational amplifier circuit 26 attempts to maintain the threshold level when it exceeds the threshold level.

This circuit is an example that does not require the operational amplifier circuit 22 (see FIG. 3) as a level shifter. That is, in this example, when the level of the differentiated waveform shown in FIG. When the output level from the transformer 21 is sufficiently higher than the hysteresis, the level shift may not be performed. In the case of this example, when a DC signal is supplied, the potentials of the inverting and non-inverting input terminals of the operational amplifier circuit 26 become equal,
Since they are canceled, the capacitors C1 and C2
It is necessary to perform a DC cut. That is, since the impedance when the rotary transformer 21 is viewed from the operational amplifier circuit 26 becomes small in the low frequency range, the differential input portion of the operational amplifier circuit 26 becomes equipotential, and the positive feedback is no longer expensive. C2 increases the impedance in the low frequency range.

Here, assuming that the input voltages of the differential input section of the operational amplifier circuit 26 are Vi + and Vi- and the output voltages are Vo + and Vo-, the equations shown by the equations (3) and (4) hold in an equilibrium state. .

[0055]

## EQU3 ## Vi + = Vbb × r26 / (r21 + r26)
+ Vo + × r21 / (r21 + r26)

[0056]

## EQU4 ## Vi− = Vbb × r25 / (r22 + r25)
+ Vo-xr22 / (r22 + r25)

Here, | Vi + −Vi− | is the hysteresis of this circuit. Resistance value r of resistors R21 and R22
When 21 and r22 are equal and the resistance values r25 and r26 of the resistors R25 and R26 are equal, the following equation 5 is established.

[0058]

| Vi + −Vi− | = | Vo + −Vo− | × r21
/ (R21 + r26)

If | Vi + −Vi− | is a certain level or more (eg, 0.2 V or more), the output voltages Vo + and V
Since o- may be the high level Vh and the low level Vl of the ECL, the expression shown in Expression 5 can be replaced by the expression shown in Expression 6 below.

[0060]

| Vi + −Vi− | = | Vh−Vl | × r21 /
(R21 + r26)

When the differential waveform is supplied via the capacitors C1 and C2, the equilibrium state is broken, and the polar inversion occurs. In order for the polar inversion to occur, the level of the differential waveform supplied via the capacitors C1 and C2 needs to be large enough to overcome the hysteresis and become the ECL threshold level.

Next, the operation of the circuit shown in FIG. 4 will be described. The original signal output from the recording system 2 has a differential waveform as shown in FIG. 2B due to the influence of low-frequency cutoff when passing through the rotary transformer 21.

The output having this differentiated waveform is the output of the capacitor C
After its DC component is cut by 1 and C2, it is supplied to the operational amplifier circuit 26. The operational amplifier circuit 26 is shown in FIG.
By detecting the rise and fall of the input signal waveform shown in B and applying positive feedback, the operation of maintaining the level when the level of the differentiated waveform is above the threshold in both cases of rising and falling Then, the same signal as the original signal is obtained as shown in FIG. 2C.

The signal restored to the same signal as the original signal is subjected to current amplification in the head driver 25 and then to the head 12
Is recorded on the magnetic tape 13 by the head 12 so as to form an inclined track.

As described above, in this example, the DC component of the original signal, which has become a differential waveform due to the influence of the low-frequency cutoff by the rotary transformer 21, is cut by the capacitors C1 and C2, and the level of this original signal is calculated by the operational amplifier circuit. Since the signal is restored as the original signal at 26, the cancel operation of the operational amplifier circuit 26 due to the DC component is prevented, and the channel for the clock signal and the like other than the channel of the signal to be recorded is reduced to reduce the circuit scale. By doing so, low power consumption and low cost can be achieved, and high-speed transmission and multi-channel can be supported.

The above embodiment is an example of the present invention.
It goes without saying that various other configurations can be adopted without departing from the spirit of the present invention.

[0067]

According to the present invention described above, the output from the rotary transformer is shaped by the waveform shaping means and recorded on the recording medium by the recording means, so that channels other than the channel of the signal to be recorded are reduced. By reducing the circuit scale, power consumption and cost can be reduced, and high-speed transmission and multi-channel operation can be supported.

Further, according to the present invention described above, the waveform shaping means detects the rising and falling edges of the output signal which has undergone the low-frequency cutoff by passing through the rotary transformer and has become a differential waveform of the original signal, and Since the high level and the low level are maintained by applying the positive feedback to restore the original signal, in addition to the above-described effects, a good original signal can be restored with a simple circuit configuration.

[0069]

Further, according to the present invention described above, the level of the output from the rotary transformer is shifted by the level shift means provided in the preceding stage of the comparing means. The system other than the main line is not required, the circuit scale is minimized, the case where the signal level supplied to the comparison means is small, and a good original signal can be restored.

Further, according to the present invention, since the comparing means performs the comparing operation with the hysteresis characteristic, the original signal can be restored with the simplest circuit configuration in addition to the above-mentioned effects.

Further, according to the present invention as described above, a first resistor is connected to one input terminal of the operational amplifying means, and a second resistor is connected to the other input terminal of the operational amplifying means. The one input terminal and the first output terminal of the operational amplifier are connected to a third
And the other input terminal and the second output terminal of the operational amplifying means are connected by a fourth resistor to perform the comparing operation. In addition, simplification of the channel can be realized without a particularly complicated circuit configuration.

Further, according to the present invention, the hysteresis of the comparing operation of the comparing means is controlled by the ratio of the resistance values of the first resistor and the third resistor. A desired hysteresis characteristic can be obtained, and it is possible to cope with recording apparatuses of various specifications.

According to the present invention described above, the DC component is cut by the capacitor disposed between the rotary transformer and the waveform shaping means, so that the operation of canceling the operation and amplification means by the DC component can be prevented. By reducing the circuit scale by reducing channels other than the channel of the signal to be recorded, lower power consumption,
The cost can be reduced, and high-speed transmission and multi-channel can be supported.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a basic configuration of an embodiment of a recording apparatus according to the present invention.

FIG. 2 is a waveform chart for explaining an embodiment of the recording apparatus of the present invention.

FIG. 3 is a configuration diagram showing a specific example 1 of the recording apparatus of the present invention.

FIG. 4 is a configuration diagram showing a specific example 2 of the recording apparatus of the present invention.

FIG. 5 is a timing chart for explaining the operation of a conventional recording / reproducing apparatus.

FIG. 6 is a configuration diagram illustrating an example of a conventional recording apparatus.

[Explanation of symbols]

2 Recording system 12 Head 13 Magnetic tape 15, 21 Rotary transformer 16 Waveform shaping circuit 22, 23, 26 Operational amplifier circuit 25 Head driver R1, R2, ... R11, R20, R21, ...
・ R28 resistor C1, C2 capacitor

Claims (6)

(57) [Claims] A signal processing means for processing an information signal to be recorded; a rotary transformer for transmitting a recording signal from the signal processing means to a head; A waveform shaping means for detecting a rising edge and a falling edge of an output signal which has become a differential waveform of the original signal, and maintaining a high level and a low level by applying positive feedback to restore the original signal; Recording means for recording the output from the recording medium on a recording medium. 2. The recording apparatus according to claim 1, further comprising a level shifter for shifting a level of an output from the rotary transformer before the waveform shaping unit. 3. The recording according to claim 1, wherein said waveform shaping means has a comparing means for comparing the output of said rotary transformer, and said comparing operation has a hysteresis characteristic. apparatus. 4. The comparing means comprises: a first resistor connected to one input terminal of the operational amplifying means;
A second resistor is connected to the other input terminal of the operational amplifier, one input terminal and a first output terminal of the operational amplifier are connected by a third resistor, and the other terminal of the operational amplifier is connected to the other terminal. 4. The recording apparatus according to claim 3, wherein the input terminal and the second output terminal are connected by a fourth resistor. 5. The recording apparatus according to claim 4, wherein a hysteresis characteristic of said comparing means is controlled by a ratio between resistance values of said first resistor and said third resistor. 6. A DC cut capacitor disposed between the rotary transformer and the waveform shaping means, wherein an output level from the rotary transformer to the comparing means provided in the waveform shaping means is equal to the comparing means. 6. The recording apparatus according to claim 3, further comprising recording means for recording an output from said waveform shaping means on said recording medium when said hysteresis is larger than the hysteresis.