JPH028428Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a lumped constant type or distributed constant type variable delay line that is a combination of an inductance element and a capacitor, and particularly relates to the improvement of an ultrahigh-speed variable delay line with good rise characteristics and output waveform distortion. .

Conventionally, this type of variable delay line, for example, a lumped constant type variable delay line, has a structure shown in FIGS. 1 and 2.

That is, an inductance element 3 is formed by space-winding a conductor strip 2 around a rod-shaped bobbin 1 in the form of a single-layer solenoid, and an inductance element 3 is formed on a dielectric plate 6 provided on the inner bottom surface of a case 4 with an open top via a ground plate 5. The elements 3 are stacked horizontally, and a fixed contact row 7 is formed on the upper surface of the horizontally placed inductance element 3, with the conductor strip 2 on the upper surface serving as a fixed contact.
The ground plate 5 is connected to the input/output side ground terminals 8 and 9 installed separately on both ends of the bottom plate of the case 4, and one end of the conductor strip 2 of the inductance element 3 is connected via an internal resistor Ro (not shown). The other end of the conductor strip 2 is connected to the input-side ground terminal 8 , and the other end of the conductor strip 2 is connected to the output terminal 10 installed near the output-side earth terminal 9 , while the input terminal 11 is installed near the input-side earth terminal 8 . The connection electrode 12 connected to the inductance element 3 is supported along the fixed contact row 7 in the middle of the case 4 above the inductance element 3, and the connection electrode 12 is inserted into the spring holder 13 disposed between the inductance element 3 and the connection electrode 12. Fixed contact row 7 while in contact with
It is constructed by housing a movable contact spring 14 that slides thereon.

The reference numeral 15 indicates a composite capacitor formed by sandwiching the dielectric plate 6 between the ground plate 5 and the conductor strip 2, and the reference numeral 16 indicates the head of the spring holder 13 protruding from the slit 17 formed in the connection electrode 12. It is a knob attached to the

The variable delay line configured in this way is
6 is moved along the slit 17 of the connection electrode 12, the movable contact spring 14 slides on the fixed contact row 7 while repeating single contact with a fixed contact and double contact with an adjacent fixed contact. Since the fixed contact is connected to the connection electrode 12, the delay time can be varied.

However, in the conventional variable delay line, the connection electrode 12 in contact with the movable contact spring 14 extends from the output terminal 10 of the inductance element 3, that is, the fixed contact on the side with a large delay time, toward the fixed contact on the side with a small delay time. Generally, it is constructed so that it reaches the open end.

Therefore, for example, when the movable contact spring 14 is positioned at the right end in FIG. 1, the input pulse from the input terminal 11 advances from the left to the right on the connection electrode 12, as seen from the equivalent circuit in FIG. The fixed contact 7a at the right end is connected via the movable contact spring 14 at the right end.
The fixed contact 7a divides the input energy into two, one of which is output from the output terminal 10 with the minimum delay time, and the other of which travels to the left along the delay line and is absorbed by the internal resistor Ro. In this case, some mismatch occurs in the connection electrode 12 when viewed from the input terminal 11, but it is not a large mismatch, so the input pulse waveform at the input terminal 11 is reflected by the mismatch, as shown by the solid line in FIG. The delay characteristics are not deteriorated.

However, when the movable contact spring 14 is positioned to the left end in FIG. 1, as shown in FIG.
The input pulse from 1 travels slightly from left to right through the connecting electrode 12 and is immediately applied to the leftmost fixed contact 7b via the movable contact spring 14, where the input energy is divided into two. One goes to the right on the delay line and is output from output terminal 10 with the maximum delay time, and the other goes to the left end and is output from the internal resistance.
Absorbed by Ro.

In this case, since a considerable portion of the connection electrode 12 exists on the right side of the connection point of the movable contact spring 14, that is, on the output terminal 10 side, a capacitive impedance is connected to the connection point of the connection electrode 12 and the movable contact spring 14. As a result, the matching at the connection point as seen from the input terminal 11 is greatly deteriorated. Note that the extent to which the matching is deteriorated decreases as the movable contact spring 14 is moved to the right side of the connection electrode 12, that is, toward the open end or the output terminal 10 side and the delay time is decreased.

As a result, the rise characteristics of the output pulse deteriorate, distortion of the output waveform increases, and delay characteristics deteriorate. The broken line in FIG. 4 is the input pulse waveform at the input terminal 11 where reflection has increased and deteriorated due to increased mismatch.

The above-mentioned mismatch increases as the delay time increases, worsening the rise and distortion of the output pulse, and in general, the rise characteristics of the delay line itself also tend to worsen as the delay time increases. Therefore, there is a problem in that the above-mentioned mismatch has an adverse effect on the delay characteristics, and the deterioration of the delay characteristics is promoted.

The present invention was made to solve these conventional drawbacks, and it is a variable delay line with a simple structure that does not deteriorate delay characteristics such as rise characteristics and output waveform distortion even when the delay time is changed. The purpose is to provide.

To achieve this objective, the present invention includes an inductance element formed by winding a conductor, a capacitor combined with this inductance element, a fixed contact array formed on the inductance element, and a fixed contact array arranged along the fixed contact array. In a variable delay line comprising a connection electrode connected to an external connection terminal, and a movable contact that slides on the fixed contact row while contacting the connection electrode, the delay time of the fixed contact row in the connection electrode The end corresponding to the minimum end of the connection electrode is used as a connection part to the external connection terminal, and the end of the connection electrode corresponding to the maximum delay time of the fixed contact array is an open end.

According to the configuration of the present invention, delay characteristics such as the rise and distortion of the output waveform are improved, and deterioration of the delay characteristics can be suppressed even when the delay time is changed.

Embodiments of the present invention will be described in detail below. In addition,
Parts common to the conventional example are given the same reference numerals.

FIG. 5 is a front view (partially shown in cross section) showing an embodiment of the variable delay line according to the present invention, and FIG. 6 is an equivalent circuit diagram thereof.

In FIG. 5, an inductance element 3 is formed by winding a conductor strip 2 in a space around the outer periphery of a rod-shaped non-magnetic bobbin 1 having a rectangular cross section in the form of a single-layer solenoid. A ground plate 5 is installed on the inner bottom of the synthetic resin case 4.
It is stacked horizontally on a dielectric plate 6 fixed via a dielectric plate 6 with the opposing surfaces in the longitudinal direction being the upper and lower surfaces. The dielectric plate 6, the ground plate 5 sandwiching it, and the lower conductor strip 2 of the inductance element form an elongated composite capacitor 15, and a capacitor is connected between the conductor strip 2 and the ground for each turn of the inductance element 3. , a lumped constant type delay line is constructed in which one turn corresponds to an inductance L for one section.

Each conductor strip 2 on the upper surface of the inductance element 3 serves as a fixed contact 7a, 7b... (not shown in FIG. 5), and these fixed contacts 7a, 7b...
A fixed contact row 7 is formed by. The fixed contact array 7 can be formed not only by a part of the conductor strip 2 but also by another lead-out contact connected to the conductor strip 2.

At both longitudinal ends of the bottom plate of the case 4,
An input terminal (external connection terminal) 11 and an input side ground terminal 8, and an output terminal (external terminal) 10 and an output side ground terminal 9 are installed. Input terminal 1
1 and the input side ground terminal 8 are arranged at the left end in FIG. 5, and the output terminal 10 and the output side ground terminal 9
is located at the right end in the figure, the ground plate 5 is connected to the input/output side ground terminals 8 and 9, and one end of the conductor strip 2 of the inductance element 3 (left end in the figure)
is connected to the input side ground terminal 8 via an internal resistor Ro (not shown), and the other side (right end in the figure)
serves as an output terminal and is connected to the output terminal 10.

A connection electrode 12 is supported in the middle of the case 4 so as to close the case 4 above the inductance element 3. The right end of the connection electrode 12 in FIG. Output terminal 10
The coaxial cable 18 extends along the inner surface of the side near the output terminal 10 and is connected to a line having a predetermined impedance at the bottom of the case 4, for example, a coaxial cable 18 with a characteristic impedance Ro/2.
extends along the side of the composite capacitor 15 and connects to the output terminal 1.
It is connected to the input terminal 11 at the left end in FIG. 5, which is far from 0.

A spring holder 13 is arranged between the connection electrode 12 and the inductance element 3, and this spring holder 13
A movable contact spring 14 is housed inside. This movable contact spring 14 slides on the fixed contact row 7 while contacting the connection electrode 12, and repeats single contact of one fixed contact and double contact of adjacent fixed contacts to contact any fixed contact 7a, 7b. ...Connect electrode 13
is connected to.

A slit 17 (not shown in FIG. 5) is formed in the connection electrode 12 along the fixed contact row 7 of the inductance element 3. The upper part of the spring holder 13 partially protrudes from this slit 17, and the knob 1
6 is installed.

The variable delay line configured in this way is
6 to position the movable contact spring 14 at the right end of the fixed contact row 7 in FIGS. added to,
Proceed slightly from right to left in this connection electrode 12 and immediately connect the fixed contact 7 at the right end via the movable contact spring 14.
added to a. The input energy is divided into two by this fixed contact 7a, and one is outputted to the output terminal 10 with the minimum delay time of one section, and the other travels to the left on the delay line for several sections and is absorbed by the internal resistance Ro. Ru.

In this case, since a considerable portion of the connection electrode 12 exists on the left side of the connection point of the movable contact spring 14, that is, on the side of the fixed contact 7b having a large delay time as described later, a mismatch occurs at that connection point as in the conventional example. . However, the movable contact spring 14 is
When moving to the right end of the fixed contact 7a where the minimum delay time can be obtained, the rise characteristics of the delay line itself and the distortion of the output waveform are small, so there may be some distortion due to mismatch between the connecting electrode 12 and the movable contact spring 14. Deterioration of delay characteristics is not a problem.

On the other hand, move the knob 16 to release the movable contact spring 1.
4 is located at the left end of the fixed contact row 7, the input pulse from the input terminal 11 travels to the left from the connection part 12a of the connection electrode 12 via the coaxial cable 18, and is transmitted via the movable contact spring 14 at the left end. and is added to the leftmost fixed contact 7b. The input energy is divided into two at this fixed contact 7b, one of which travels along the delay line in the direction of the output terminal 10 and is output to the output terminal 10 with the maximum delay time for multiple sections, and the other is opposite to the output terminal 10. direction and is absorbed by the internal resistance Ro.

In this case, since the movable contact spring 14 contacts the connection electrode 12 at a portion near the open end, a slight misalignment occurs but not a large misalignment, and the movable contact spring 14 is positioned at the fixed contact 7a with a short delay time. This is the state in which the inconsistency is improved the most compared to the case where the

When the knob 16 is moved in this way and the movable contact spring 14 is slid on the fixed contact array 7, an output with a delay time of a predetermined section is obtained at the output terminal 10, while the connection electrode 12 and the movable contact spring 14 are moved. The smaller the delay time, the worse the mismatch at the connection point with the contact spring 14, while the larger the delay time, the better.

Therefore, in a variable delay line, the tendency of rise characteristics and distortion of the output waveform due to an increase in the delay time in the variable delay line itself and the tendency of mismatch due to movement of the movable contact spring 14 act in opposite directions. In fact, even if the delay time is changed, the rise characteristics and distortion of the output waveform do not change and are maintained well.

This means that the end of the fixed contact array in the connection electrode corresponding to the minimum delay time is connected to the input terminal and an input signal is applied, and the end corresponding to the maximum delay time is connected as an open end. This is due to becoming.

FIG. 7 shows another embodiment of the present invention, in which the input terminal 11 and the input side ground terminal 8 are implanted near the output terminal 10 on the bottom plate of the case 4,
The connection part 12a of the connection electrode 12 is connected to the coaxial cable 18.
input terminal 1 directly on the output terminal 10 side without going through
It is configured by connecting to 1.

Further, although not shown, the present invention will be explained with reference to FIG. 11, while the output terminal 10 is installed apart from the input terminal 11, and the output end of the inductance element 3 is connected to the output terminal 10 via a coaxial cable as described above.

Furthermore, the connection electrode 12 does not need to be connected to the input terminal 11 as an external connection terminal via the coaxial cable 18, but may be connected by a line, for example, a twisted pair of wires, having a predetermined impedance in accordance with the arrangement of the terminals. Connection can be made via the connection portion 12a of the connection electrode 12.

Furthermore, in the present invention, instead of forming the inductance element 3 by winding the conductor strip 2 around the bobbin 1, it is also possible to form the inductance element 3 by winding the conductor wire in a single-layer solenoid shape in a space, or by wrapping the conductor wire around the outer periphery of the bobbin. It is also possible to form a solenoid by providing a conductor layer and cutting its outer periphery by conventionally known means. Also,
The inductance L in each section of the delay line does not necessarily need to be formed on the same bobbin, and the bobbin may be omitted in some cases.

As explained above, according to the variable delay line of the present invention, delay characteristics such as rise characteristics and output waveform distortion are improved, and even if the delay time is changed, these delay characteristics can be maintained favorable.

In the above embodiment, a lumped constant type variable delay line was explained as an example, but the present invention is a distributed constant type variable delay line constructed by combining a conductor forming an inductance element with a conductor for forming a capacitance. It can also be implemented in

[Brief explanation of drawings]

1 and 2 are a front view and a side view (both partially shown in section) showing a conventional variable delay line,
Figures 3 and 4 are equivalent circuit diagrams and output waveform diagrams of the variable delay line shown in Figure 1, and Figures 5 and 6 are
The figures are a front view (partially shown in cross section) and an equivalent circuit diagram showing one embodiment of the variable delay line of the present invention, and FIG. 7 is a front view (partially shown in cross section) showing another embodiment of the present invention. It is. 1...Bobbin, 2...Conductor (conductor strip), 3...
Inductance element, 4... Case, 7... Fixed contact row, 7a, 7b... Fixed contacts, 10... External terminal (output terminal), 11... External connection terminal (input terminal), 12... Connection electrode, 12a...Connection part,
14...Movable contact (movable contact spring), 15...Capacitor, 18...Predetermined impedance line (coaxial cable).

Claims (1)

[Claims for Utility Model Registration] (1) An inductance element formed by winding a conductor;
A capacitor that forms a delay line in combination with this inductance element, a fixed contact row consisting of a plurality of fixed contacts provided on the inductance element, and a connection electrode arranged along this fixed contact row and connected to an external connection terminal. and a movable contact that slides on the fixed contact row while contacting the connection electrode and selects an arbitrary fixed contact from the fixed contact row and connects it to the connection electrode, In a variable delay line whose delay time is changed by A variable delay line characterized in that the end corresponding to the maximum end of the delay time of the contact array is an open end. (2) The variable delay line according to claim 1, wherein the connection part of the connection electrode is connected to an external connection terminal located apart from the external terminal of the inductance element via a predetermined impedance line. . (3) The variable delay line according to claim 1, wherein the connection portion of the connection electrode is connected to an external connection terminal disposed near the external terminal of the inductance element. (4) The variable delay line according to claim 1, wherein the inductance element is connected via a predetermined impedance line to an external terminal located apart from the external connection terminal of the connection electrode.