JPS61116408A - Dielectric rotating coupler - Google Patents

Abstract

PURPOSE:To transmit and receive a high transfer signal by connecting an oscillator to oscillate by a resonance frequency of the third dielectric body line to either of the first or second dielectric body line and modulating a variable impedance circuit connected to the other side by the signal to be transferred. CONSTITUTION:An oscillating circuit 15 oscillates a resonance frequency of the third line 30 as an oscillating frequency, and when the capacity of a variable impedance circuit 26 is changed by a reproducing signal of a rotary head 25 outputted from the rotation side, the resonance frequency of the third line 30 coupled with the second line 20 is also changed. For that reason, the oscillating circuit 15 is FM-modulated by the reproducing signal from the rotary head 25, and the reproducing signal of the rotary head 25 is outputted to a demodulating circuit 16 connected to the first line 10. Thus, a coupling frequency band of a transfer signal is wide, the prescribed coupling condition can be obtained at any place of the rotary body and the high transfer signal can be transmitted and received.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a coupler using a dielectric line,
In particular, the present invention relates to a dielectric rotary coupler that is useful when transmitting electrical signals to a rotating body or receiving electrical signals output from a rotating body.

[Conventional technology]

When two transmission lines made up of dielectric lines are placed close to each other and a signal is supplied to one dielectric line, the signal energy propagating through this dielectric line will couple to the other dielectric line. is known (Reference: Institute of Electronics and Communication Engineers Technical Research Report Microwave VOL18.N093.198
1.7.24°MW81-37).

This point will be explained in detail below.

Figure 5 shows an example of a line made of a dielectric material (relative permittivity (1)). dielectric constant ε
It is placed in a medium (including air) with 2.

One end 1a of this dielectric line (hereinafter simply referred to as line) 1
Microwave or millimeter wave (IGH2) with higher power P1
When an electromagnetic wave (up to several 100 GHz band) is input, this electromagnetic wave is confined to the line 1 and propagates in the Z-axis direction, and the terminal 1
It can be taken out as electric power P2 from the b side.

In this case, even if the line 1 made of dielectric material is bent, the electromagnetic waves propagate along the line 1.

The mode of electromagnetic waves propagating within the line 1 varies depending on the frequency of the input signal, the cross-sectional shape and dimensions of the line 1, the relative permittivity ε2 of the medium surrounding the relative permittivity (ε1) of the line 1, etc., and these can be adjusted appropriately. If it is set to a certain value, the transverse mode of the electromagnetic wave propagating within the line 1 can be made into a single propagation waveform.

Moreover, the propagation wavelength can be set to the order of several cm-0.1 mm.

Next, a coupler formed by such a line will be explained.

As shown in FIG. 6, the distance 8i between the first line 1 and the distance d1 is
Then, a second line 2 made of a dielectric material is arranged in parallel.

The electromagnetic wave of the power P1 inputted from one end 1a of the first line 1 propagates in two axial directions as described above, but 2=2. When the second line 2 is placed at the point, electromagnetic waves (indicated by thin lines) propagated from this point begin to be coupled to the second line 2. This coupling is based on a change in the propagation mode, as will be described later, and can be seen as a phenomenon in which electromagnetic waves propagating within the first line 1 gradually seep into the second line 2. The power P2 coupled to the second line 2 is Z=
It reaches a maximum at point 72, and as the electromagnetic wave further advances, it is reversely coupled from the second line 2 to the first line 1, and z = 23
A large part of the power P2 coupled at the point is returned to the first line 1.

Z2-Z, =23-22 =Lo is called the coupling length of the dielectric line.

Such a transition in electromagnetic wave energy is caused by a difference in phase constant between an even mode propagating wave and an odd mode propagating wave propagating in the dielectric line.

For example, as shown in Fig. 7, if the first line 1 and the second line 2 are one dielectric line, two modes, an even mode wave S and an odd mode wave A, propagate while vibrating. It appears that there is.

At this time, the phase constant of the even mode wave S in the Z-axis direction is βzs
, the phase constant in the odd-mode wave direction is β7A, and the coupling length is as described above. is expressed as.

In order to maximize the electromagnetic wave energy coupled from the first line 1 to the second line 2, it is sufficient to set the overlapping portion of both lines to have a coupling length Lo. If the line 2 is bent or cut at the coupling length L0, the electromagnetic wave propagation mode will be disturbed at this point, making it impossible to obtain a good coupling state.

Therefore, as shown in FIG. 8, the first... z from the point 2-7o on the second lines 1 and 2
'=z, up to the point, 2=2. If the parallelism is gradually broken from 2=2. After that,
The phase constant βzs+β2A will also change. That is, the phase constant β2S.

β7A is a function of distance #Z.

Therefore, from z=Zo, 2=2. In addition to the combined long sentences up to 2. =2. The actual joint length is the sum of the long joint length from Z-73 to Z-73.
As the distance between 2 increases, the coupling decreases rapidly, so at most 2=2. The 6 sentences of connective length from to Z-72 are converted to 2 above.
=2. It is sufficient to add it to the connected long sentences up to, and the six connected sentences are calculated by.

Therefore, in the case of Figure 8, the effective bond length is L=u+Δ
When the effective coupling length matches the coupling length LO described above, maximum power is coupled from the first line 1 to the second line 2.

FIG. 9 is a schematic diagram showing an embodiment of a dielectric rotary coupler previously proposed by the applicant of the present application using such a coupling effect.
Reference numeral 10 denotes a first line on the fixed side, which is made of a substantially straight dielectric material.

An antenna 11 is installed at one end of the first line 1o, and a non-reflection termination 12 is provided at the other end. Then, for example, the video signal Vin is supplied to the modulator 13 via the amplifier 14, and the modulator 13 generates, for example, a microwave (millimeter wave).
An FM modulated signal is input from the antenna 11.

Reference numeral 20 denotes a second line provided on a rotating body (not shown), and like the first line 10, an antenna 21 and a non-reflection termination 22 are provided at both ends.

When the rotating body is a rotating head of a VTR, a demodulator 23. Rotating head 25 via amplifier 24
Signals are offered as candy.

30 is the above-mentioned No. 1. A ring-shaped third line is shown close to the second line 10.20 and in particular arranged around the center of rotation P of the second line 20.

In such a dielectric rotary coupler, the first line 10
When an electromagnetic wave with a power of Pl is injected from the antenna 11 of do. And then the third track 3
0 and is coupled to a second line 2o which is rotating close to 0. In this case, since the third line 3o is ring-shaped, 2πR=nλg (where R is the radius of the third line 30, λg is the propagation wavelength,
n is an integer).

Therefore, when the frequency f of the electric power P1 input from the antenna 11 changes, the result as shown in FIG. 10(a).

As shown in Figure 10(b), the combined power "2 +
P3 changes periodically, for example, resonance points f,, f2,
Since maximum power is coupled from the first line 10 to the second line 20 at point f3, either resonance point (f+,
f2, f3) can be used to form a circuit combiner.

[Problem that the invention seeks to solve]

However, if the tan δ of the dielectric is large, the coupling frequency band Δf at the resonance point fl + f2 + f3 where the coupling is maximum
(width of 3 dB drop from the peak point) becomes extremely narrow, resulting in a problem of less transmitted information. Further, in order to widen the coupling frequency band Δf, it is sufficient to lower the Q value at the resonance point, but this poses a problem in that transmission loss increases.

This invention was made to solve this problem,
The ring-shaped resonator formed by the third line is used as an element that determines the oscillation frequency of the microwave oscillator,
By changing the resonant frequency of this ring-shaped resonator depending on the signal to be transmitted, a wide-band dielectric rotary coupler can be obtained.

[Means for solving the problem] A third dielectric line disposed close to both the first dielectric line provided on the rotating body and the second dielectric line provided on the non-rotating body. The ring-shaped dielectric line constitutes a dielectric rotating coupler, and an oscillator that oscillates at the resonant frequency of the ring-shaped third dielectric line is connected to the first ring-shaped dielectric line. or second
Connect to either one of the dielectric lines.

The variable impedance circuit connected to the other of the first or second dielectric line coupled to the ring-shaped third dielectric line is configured to be modulated by the signal to be transmitted.

[Effect]

When the variable impedance circuit is modulated by the signal to be transmitted, the resonant frequency of the ring-shaped third dielectric line also changes in accordance with the signal. Therefore, this ring-shaped third
The oscillation frequency of an oscillator using the dielectric line as a resonant element is frequency-modulated by the transmission signal.

The frequency modulated carrier wave is transmitted to the first . Since it is coupled to either of the second dielectric lines, if a demodulation circuit is connected to the first or second dielectric line on the signal receiving side, this demodulation circuit receives the original modulated signal. can be detected.

In this case, the first. Second. Since the third dielectric line is in the same coupling state even when the rotating body is rotating,
Depending on the installation location of the modulation circuit consisting of a variable impedance circuit and the demodulation circuit, it is possible to combine and transmit signals output from the rotating side to the non-rotating side, and signals input from the non-rotating side to the rotating side. .

〔Example〕

FIG. 1 shows a dielectric rotating coupler showing one embodiment of the present invention, and the same symbols as in FIG. 9 indicate the same parts. 15 is an oscillation circuit connected to the first line 10, and this oscillation circuit 15 is configured to oscillate at the resonant frequency of the ring-shaped third line 30 coupled to the first line 10. There is. Reference numeral 16 indicates a demodulation circuit for FM modulated waves. A variable impedance circuit 26 made of a varicap (variable capacitance diode) or the like is connected to the second line 2o provided on the circuit body side, and a reproduced signal from the rotary head 25 is transmitted to the amplifier 24, for example. It is configured to be supplied via.

According to such a dielectric rotary coupler, the oscillation circuit 15 oscillates using the resonant frequency of the third line 30 as the oscillation frequency, but the variable impedance circuit 26 is activated by the reproduction signal of the rotary head 25 output from the rotation side. When the capacitance of the third line 30 coupled to the second line 20 changes,
The resonant frequency of will also change. Therefore, since the oscillation circuit 15 is FM-modulated by the reproduction signal from the rotary head 25, the reproduction signal from the rotary head 25 is outputted to the demodulation circuit 16 connected to the first line 1o.

FIG. 2 shows an embodiment of a dielectric rotary coupler for supplying recording signals to the rotary head 25, and the same symbols as in FIG. 1 indicate the same parts.

Reference numeral 27 indicates a demodulation circuit provided on the rotating side, 40 indicates a fourth line on the non-rotating side coupled to the third line 30, and this $4 line 40 includes a recording signal source 41, an amplifier 42, A variable impedance circuit 43 whose impedance is variable according to a signal supplied from the terminal is connected thereto.

In this embodiment as well, the oscillation circuit 15 oscillates at the resonant frequency of the third line 3o, as in FIG.
A fourth line 40 is connected to the fourth line 40, and is formed so that its resonant frequency changes depending on the recording signal.

Therefore, since the carrier wave FM modulated by the recording signal is coupled to the second line 2o on the rotating side, when this is demodulated by the demodulation circuit 27, the recording signal supplied from the non-rotating side is detected. This signal is sent to rotating head 2.
5 can be supplied.

This first. In both of the second embodiments, the frequency coupled between the first and second lines 10 and 20 is always the same as that of the third line 3.
Since it is equal to the resonant frequency of 0, it has the characteristic that it is not subject to band limitation as seen in the dielectric rotary coupler shown in FIG. 9 described above, and the transmission frequency band can be widened.

Note that although FIGS. 1 and 2 show the case where signals are output from the rotating head 25 and the case where signals are supplied to the rotating head 25, the demodulating circuit 27 is provided on the rotating side,
It goes without saying that a transmitting/receiving circuit for the rotary head 25 may be configured by providing a variable impedance circuit 26 and switching these circuits using a switch circuit.

3 and 4 show other embodiments of the present invention in which an oscillation circuit 15 is added to the second line 20 provided on the rotating side, and show the same parts as FIGS. 1 and 2. are given the same symbol.

Although a detailed explanation will be omitted, in this embodiment as well, the third line 30 is used as a resonant element, and the signal from the oscillation circuit 15, which is FM modulated by the reproduction signal or the recording signal, is transmitted between the rotating body and the non-rotating body. The combined frequency is . Therefore, there is an advantage that the combined frequency band (Δf) becomes wider.

Above, we have described the case where the dielectric rotating coupler of the present invention is applied to a magnetic recording/reproducing device, but it can also be used to equalize a wide bandwidth signal between a rotating body and a non-rotating side. It goes without saying that it can be done.

〔Effect of the invention〕

As explained above, the dielectric rotary coupler of the present invention has the following features: A ring-shaped third dielectric line is interposed as a resonant element with respect to the second dielectric line, and the oscillation frequency serving as a carrier wave is modulated by the signal to be transmitted, so the combined frequency band of the transmission signal is It has the advantage of being wider.

Further, this dielectric rotary coupler has the advantage of being able to obtain a predetermined coupling state at any position on the rotating body, and at the same time being able to transmit and receive high transmission signals that cannot be achieved with conventional rotary transformers.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the dielectric rotary coupler of the present invention. FIG. 1 is a configuration diagram for coupling signals from a rotating body to a non-rotating body, and FIG. A configuration diagram for coupling signals from the rotating body side to the rotating body, FIGS. 3 and 4 are configuration diagrams of a dielectric circuit coupler showing other embodiments of the present invention,
Figure 5 is a perspective view showing an example of a dielectric line, and Figure 6 is a perspective view of an example of a dielectric line.
．． An explanatory diagram of the electromagnetic wave energy propagating through the second dielectric line, FIG. 7 is an explanatory diagram of the propagation mode, FIG. 8 is an explanatory diagram of the coupling length of the first and second dielectric lines, and FIG. 9 is an explanatory diagram of the coupling length of the first and second dielectric lines. FIG. 10(a) is a schematic diagram showing the prior art when a dielectric rotary coupler is adopted as a rotary head. (b) is the first. Second. It is a graph which shows the coupling power ratio of a 3rd line. In the figure, 10 is a first line, 20 is a second line, 30 is a third line, 40 is a fourth line, 15 is an oscillation circuit, 16 is a demodulation circuit, and 26 is a variable impedance circuit. Figure 9 Vin A Figure 10 (a) (b) □f@7makif

Claims (1)

[Claims] A first dielectric line provided on the rotating body, a second dielectric line provided on the non-rotating body, and a ring-shaped dielectric line coupled to the first and second dielectric lines. In a dielectric rotating coupler configured with a third dielectric line, an oscillator that oscillates at the resonant frequency of the third dielectric line is connected to either the first or second dielectric line. and a variable impedance circuit connected to the other dielectric line or the fourth dielectric line coupled to the third dielectric line is configured to be modulated by the signal to be transmitted. Body rotation combiner.