JPH0210602B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a lumped constant variable delay line that combines a coil made of a plurality of turns of a conductor and a capacitor, and particularly relates to a compact variable delay line that can finely switch the delay time. Regarding variable delay lines.

[Prior art and its problems]

Conventionally, this type of variable delay line is known in which a plurality of coil units and a plurality of capacitors are combined and connected, and the delay time is changed by switching and connecting the coil units.

However, in a variable delay line configured in this manner, if the delay time per coil unit is td, the delay time can only be changed by an integral multiple of td.

As a result, when it is incorporated into an electronic device such as a computer, there is a drawback that the optimum delay time cannot be adjusted.

In addition, in order to increase the resolution of delay time, the number of coil units must be increased, which tends to increase the size and height of the coils. This was developed to solve the drawbacks of the conventional method, and the purpose is to provide a small and inexpensive variable delay line that has a resolution approximately twice as large as the number of switching contacts.

[Structure and effects of the invention]

In order to achieve this object, the present invention connects a plurality of coils made by winding a plurality of turns of a conductor in series with a predetermined coupling coefficient, and connects a capacitor between the connection point of adjacent coils and the ground. A fixed contact row is formed by the fixed contacts provided at each of the connection points, and single contact with each fixed contact forming this fixed contact row and double contact between adjacent fixed contacts are repeated alternately. The movable contact means is arranged so as to move by moving.

According to such a configuration, it is possible to obtain a variable delay line having a resolution approximately twice as large as the number of fixed contacts provided at the connection points of adjacent coils, and also to have a smaller size and to keep the price low. Can be done.

[Embodiments of the invention]

The details of the present invention will be explained below.

1 and 2 are a front sectional view and a side sectional view showing an embodiment of the present invention.

In the figure, a rod-shaped non-magnetic bobbin 1 with a rectangular cross section has a plurality of coils 2 wound in series and coaxially at a predetermined pitch in a single-layer solenoid-like manner with a plurality of coils 2, forming an inductance element 3. ing.

The inductance element 3 has support portions 4 protruding from both side surfaces at both ends of the non-magnetic bobbin 1.
It is placed horizontally within the casing 5 in contact with the inner bottom of the casing 5.

A terminal plate 6 as shown in FIG. 4 is placed on the support portion 4 located above the horizontally placed inductance element 3 so as to pass over the coil 2.

The terminal board 6 has a plurality of fixed contacts 8 formed on the main surface of a thin and elongated insulating plate 6a, perpendicular to and parallel to the axial direction of the insulating plate 6a, and these fixed contacts 8 form a fixed contact array. 9 are configured.

A continuous V-shaped notch 10 is formed on the end surface of the insulating plate 6a along the axial direction. A cut groove 11 is formed in each fixed contact 8 from the direction opposite to the cut 10 to the middle of the fixed contact 8.

Note that these fixed contacts 8 are preferably formed by photoetching or the like from a printed circuit board.

At the end of each fixed contact 8 on the notch 10 side, there is a connection point between adjacent coils 2 and a capacitor 12.
is connected. Note that the connection between the connection point of the coil 2 and the fixed contact 8 is made by twisting lead wires between adjacent coils.

The capacitor 12 is made of a thin and elongated dielectric plate 12a.
A ground electrode 13 is formed on the main surface of the casing 5, and a plurality of capacitance electrodes 14 are formed at predetermined intervals on the main surface opposite the ground electrode 13. A ground electrode 13 is connected to the tip and is supported so as to extend above and parallel to the inductance element 3. The capacitive electrode 14 of the capacitor 12 and the fixed contact 8 are connected by a lead wire 16.

In this way, the inductance element 3 and the capacitor 12 are combined to form a lumped constant delay line.

Input/output terminals 17, 18 and input/output ground terminals 19, 20 are implanted at the bottom of the housing 5. The support plate 15 is connected to the input/output ground terminals 19 and 20, and the fixed contact 8 at one end of the fixed contact array 9 is connected to the output terminal 18.

A conductive plate 21 connected to the input terminal 17 is attached to the opening of the housing 5 so as to close the opening.
A concave portion 22 facing inward is formed in the conductive plate 21 along the inductance element 3 .

A spring holder 24 is disposed between the recess 22 and the fixed contact row 9 so that its upper portion protrudes from a sliding groove 23 formed in the recess 22 along the fixed contact row 9.

A sliding spring 25 curved into an arcuate shape is housed within the spring holder 24 . The sliding spring 25 has an end slidably in contact with the conductive plate 21, and has a movable contact 26 formed into a curved bulge.
is elastically brought into contact with both the individual fixed contacts 8 in the fixed contact row 9 and the adjacent fixed contacts 8, and constitutes movable contact means.

If the knob 27 attached to the upper part of the spring holder 24 is moved along the sliding groove 23, the sliding spring 25 will move between the fixed contacts 8 and the movable contacts while being biased by its elastic deformation force. 26
The fixed contact array 9
move on.

Therefore, the input terminal 17 is connected to any fixed contact 8 via the conductive plate 21, the sliding spring 25, and the movable contact 26.

Note that since the movable contact 26 is biased against the fixed contact 8, as the spring holder 24 moves,
The depressions are repeated between the fixed contacts 8 and between the cut grooves 11 in the fixed contacts 8. Therefore, an operational feeling such as a clicking sound can be obtained, and the contact between the movable contact 26 and the fixed contact 8 is ensured.

Next, the operation of the variable delay line of the present invention configured as described above will be discussed using an equivalent circuit diagram.

FIG. 3 is an equivalent circuit diagram showing the variable delay line shown in FIG. 1 including an external circuit.
6 indicates a single contact state.

In the variable delay line shown in FIG. 1, as shown in FIG. 3, a plurality of inductances L and capacitors of capacitance C are alternately connected in a ladder shape, and a coupling coefficient a is established between the inductances L in adjacent sections. The present is shown in an induced m-type configuration.

Then, the delay time td in one section is td=√(1+2)・...(1), and the characteristic impedance Ro is: becomes.

Additionally, a terminating resistor Ro is connected between the output terminals 18 and 20.
is connected, and a resistor Ro is also connected between the other end of the inductance element 3 and the ground (not shown in FIG. 1). The pulse signal source PG has an output impedance of Ro/2, and input terminals 17 and 19.
connected between.

The input signal from the pulse signal source PG is transmitted to the conductive plate 21
It is input to the fixed contact 8 via the sliding spring 25, etc.
The energy is divided into two and propagated both to the left and right from the input point. In other words, the signal propagated to the right is 1
After a delay time obtained by multiplying the delay time td for the section by the number of sections on the right side from the input point, it is output to the output terminals 18 and 20, and is absorbed by the terminating resistor Ro as a load.

Therefore, by moving the knob 27 shown in FIG. 1 and sliding the movable contact 26, the delay time of the output signals from the output terminals 18 and 20 can be changed.

On the other hand, the signal propagated to the left side of the delay line also reaches the casing 5 after a delay time multiplied by the number of sections on the left side from the input point.
It is consumed by the resistance Ro within.

Next, the operations of multiple contact and single contact in the present invention will be explained.

First, the multiple contact operation will be explained. The inductance L is transmitted from the sliding spring 25 through the movable contact 26.
The current flowing to the capacitor is divided into left and right sides at multiple contact points, and part of each flows through the two parallel-connected capacitors C, but the remaining current flows through the left and right inductances L as an equal current with opposite directions. Therefore, the electromotive force induced in the short-circuited inductance L due to the current cancels each other out, so that no short-circuit current flows and no loss occurs.

On the other hand, the inductances L adjacent to each other across the short-circuited inductance L have mutual induction on only one side, so the value of each inductance L as a delay line element is L(1+a).

Usually, the coupling coefficient a between the inductances L is
It is preferable to select it to be about 0.15, and the delay time and characteristic impedance Ro in this section should be selected as described in (2) above.
Although it is about 7% lower than the formula, it has no relation to the delay time variable function.

Next, the single contact operation will be explained.

In the case of single contact, the inductance L is not short-circuited by the movable contact 26, and part of the current flowing from the sliding spring 25 to the inductance L via the movable contact 26 flows to the capacitor C, and the rest flows in the opposite direction. A uniform current flows through the left and right inductances L.

In other words, the adjacent left and right inductances L are coupled through a single contact with a coupling coefficient of -a,
Since each of them is further coupled to the adjacent inductance L with a coupling coefficient +a, the value of each inductance becomes L(1+a-a)=L, and the value decreases compared to the case of multiple contact described above.

Therefore, in the case of single contact, the capacitance of the capacitor at the single contact point is reduced to 1/2 and the inductance L is reduced to 1/(1+a) compared to double contact, so the delay time is approximately 0.3 td shorter than in double contact.

In the variable delay line shown in Fig. 1,
The delay time is the smallest when the movable contact 26 is moved to the right, and this point serves as the reference point for the variable range of the delay time. When the movable contact 26 is sequentially moved to the left from this point, the movable contact 26 alternately repeats double contact and single contact, and the delay time of the signal obtained at the output terminals 18 and 20 is 0.3td, td with respect to the reference point. , 1.3td,
Changes to 2td, 2.3td...

Changes obtained in units of delay time td of one section as in the conventional concept of delayed delay line with taps, that is, changes in delay time obtained by repeating single contacts, td, 2td, etc. A more detailed stepwise change. becomes possible.

Furthermore, in the variable delay line of the present invention, when the knob 27 is moved, the movable contact 26 is always in contact with one of the fixed contacts 8, so that it will never turn off. Therefore, the delay time can be varied while the electronic circuit is always in operation, making adjustment easy and stabilizing the characteristics.

The present inventor has constructed a non-magnetic bobbin 1 having a rectangular cross section with a width of 3 mm, a thickness of 0.4 mm, and a length of 16 mm, and a polyurethane-coated copper wire with a diameter of 0.07 mm, the number of turns in one section is 9 turns, and the number of turns in the adjacent section. The pitch is 0.7mm, total
An inductance element 3 with 20 sections is formed, and the capacitance C of each section is 10 pF, and the coupling coefficient a is 0.15.
We selected and conducted an experiment.

As a result, the delay time td per section is calculated at 1nS.
A variable delay line containing a delay line of 20nS and a characteristic impedance Ro of 100Ω is obtained, and in the single contact position
1nS, 2nS…20nS, approximately 0.3nS at multiple contact positions,
1.3nS, 2.3nS...19.3nS were obtained.

Coil 2 in the above-mentioned inductance element 3
was formed by winding a conductive wire into a single-layer solenoid shape.
However, it is also possible to use a spiral winding or a multilayer winding, and a bobbin is not essential. Also, for example, by winding a ferrite drum core,
A delay line unit in which a tap is pulled out from the middle of the winding and a capacitor is connected can also be implemented in an inductive m-type delay line in which a plurality of delay lines are connected in cascade.

Furthermore, the movable contact means may be of any type as long as it slides by alternately repeating single contact with each fixed contact and double contact with adjacent fixed contacts.

As explained above, the present invention provides fixed contacts at the connection points of adjacent coils, and a movable contact means that slides by alternately repeating single contact with each fixed contact and double contact between adjacent fixed contacts. Since I placed it,
Since the number of coils, in other words, the delay time can be changed more finely than the number of sections, it is possible to achieve miniaturization and to keep costs low.

[Brief explanation of drawings]

1 and 2 are front sectional views and side sectional views showing one embodiment of the present invention, FIG. 3 is an equivalent circuit diagram of the variable delay line shown in FIG. 1, and FIG. 4 is shown in FIG. 1. FIG. 3 is a partial perspective view showing the vicinity of a fixed contact array. 1...Non-magnetic bobbin, 2...Coil, 3...
Inductance element, 5... Housing, 6... Terminal board, 8... Fixed contact, 9... Fixed contact row, 21...
... conductive plate, 24 ... spring holder, 25 ... movable contact means (sliding spring), 26 ... movable contact means (movable contact).

Claims (1)

[Claims] 1 A plurality of coils made by winding multiple turns of a conductor are connected in series with a predetermined coupling coefficient, and a capacitor is connected between the connection point of adjacent coils among these coils and the ground, and a capacitor is provided at each connection point. A fixed contact row is formed by the fixed contacts, and movable contact means is arranged to move by alternately repeating single contact with each fixed contact forming the fixed contact row and double contact with each other adjacent fixed contacts. A variable delay line characterized by: