JPS6016714A - Ultrasonic wave delay line - Google Patents

Abstract

PURPOSE:To obtain an ultrasonic wave delay line with small size, long delay time and high performance by allowing an ultrasonic wave irradiated from a converting element provided to an end face of a delay medium to be returned to said converting element again after the ultrasonic wave is reflected at the end face. CONSTITUTION:Only one set of a converting element 15 comprising an electrode 14 and a piezoelectric porcelain material is provided to the end face 13 of a glass-made delay medium 12 of polygon form and lead wires 16, 17 are fitted respectively to the electrode 14 and the converting element 15. The ultrasonic wave produced at the converting element 15 by the impression of an electric signal Ei is propagated along a path 18a shown in solid lines and reflected on the end face 13 on which the converting element 15 is provided and then propagated through a path 18b shown in broken lines in opposite direction as the path 18a, and returned again to the converting element 15, where the signal is converted into an electrical signal EO and extracted as a delayed signal.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ultrasonic delay line used in a comb filter used for removing VJ harm in NTSG color television receivers, cross color removal in video tape recorders, etc. Especially small high PI: f(g,
Furthermore, the present invention provides an ultrasonic delay line that can be manufactured at low cost.

The configuration of the conventional comb-shaped filler is as shown in Figure E1.
Human input signal input to input terminal f-1]i:A(===α5
lnr +) t) directly to one input terminal f-3 of the arithmetic circuit 2 (one h L, the other h' input terminal 4 to the ultrasonic delay line 6
The above two types of signals KA and EB are generated by manually inputting the delayed signal EB (=βsinω(-τ0)) which is delayed by the time to from the input signal, and then calculates the above two types of signals KA and EB. It adds (or subtracts) the result and outputs it from the output terminal 6.

In this way, in the comb filter that adds the human input signal gA and the delayed signal EB obtained by passing this human input signal to the ultrasonic delay line 5, the frequency characteristics of the output value EC are as follows: As shown in the figure, a unique comb-shaped frequency characteristic 7 is obtained in which a pass band and an attenuation band alternately appear at a period of -1 and 1 O. The comb-shaped filter is used when separating color signals and luminance signals in an NTSC television receiver to remove interference.

The super 7i wave 11ffi wire used in the above-mentioned comb filter has conventionally had a 114-wire structure as shown in FIG. That is, at the end i/ii of the slow I/L medium 8 made by force
'ii 9, 9' and an electric-to-opening energy converter f1 are attached to the converter elements 1o, 10', and now when the electric signal EA is applied to the converter element 10, it converts; The child 10 mechanically vibrates according to the frequency of the signal, and an ultrasonic wave ρ·1 is emitted into the glass delay medium 8. This rl? j, l'l waves are glass delay medium 8
As shown in the path 11 shown in FIG. 3, the transducer element 10' makes a large number of errors and reaches the transducer element r10' at the other end, causing the transducer element 10' to vibrate mechanically. It is possible to take out delayed electricity No. 111 EB according to the frequency.

The size of such an ultrasonic delay line is determined by the glass delay medium 8
The speed of sound is determined by the particle quality of the ultrasonic wave, and the number of times the ultrasonic wave is applied is determined by the shape of the glass retardation medium 8. The speed of sound in the glass delay medium 8 currently in practical use is approximately 2.
53 to 2.58km/s, and 1H (63,556μ in the NTSC system during the horizontal scanning period of a television signal)
5ec) delay ril? ]) The required path length is approximately 160 mm. Therefore, in order to downsize the ultrasonic delay line, it is necessary to design the ultrasonic delay line to increase the number of reflections. However, in the conventional 1114 configuration, which increases the number of reflections by providing a large number of reflective surfaces, unnecessary reflections occur due to the directivity of the conversion element 10, which has an unspecified delay hole. l increases, causing a practical problem. Therefore, in the ultrasonic delay line currently in practical use, the number of fouls is set to 10 or less in 1H and 12 or less in 2H, and the size of the glass delay medium is 20 x 3 in 1H.
0mm and 2, the size was about 20x60mm.

The present invention has been made in consideration of the above-mentioned conventional matters, and it is possible to achieve a small size, a long delay time, and a high Super 1' performance? This is to obtain the wave JY extension.

Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 4 shows an ultrasonic delay line according to an embodiment of the present invention, and its configuration consists of an electrode 14 and a piezoelectric ceramic on the end surface 13 of a polygonal (pentagonal in FIG. 4) glass delay medium 12. Only one set of conversion elements r16 is provided, and lead wires 16 and 17 are attached to these electrodes 14 and conversion elements 15, respectively. Note that the Nl 114 and the conversion element 15 are provided at a position closer to one side than the medium heat section on the end surface 13 of the delay medium 12.

Tree'no! The characteristic feature of the flow side is that one set of the conversion element 15 and the accompanying electrode 14 are provided in the delay medium 12, and the lead wires 16 and 17 are taken out from these to form a two-terminal configuration. , with this configuration, the ultrasonic waves generated in the conversion element 15 by the application of the electric signal EiO propagate along the path 18a shown by the solid line and convert into the conversion accumulation f1.
After being reflected at the end surface 13 where 5 is provided, the path 18a
The signal propagates along a path 18b (indicated by a broken line) in the opposite direction, returns to the conversion element 15, is converted into an electric signal Ko, and is taken out as a delayed signal. In this way, the delayed signal that reverses the first path 18a after being inverted at the end face 13 of the delay medium 12 and returns to the original conversion element 16 is conventionally called a secondary inversion. However, in this embodiment, the delayed signal due to this secondary reflection is actively used as a regular delayed signal of the ultrasonic delay line.

In other words, the ultrasonic delay line of this example has a delay of 2.
By using second-order reflections, a propagation path of 2 (7'H) can be obtained, and the delay time can be doubled. Therefore, in order to obtain the desired delay characteristics, it is necessary to It is possible to use a foreign delay medium, and the ultrasonic delay line can be made significantly smaller.Also, since no processing has been done on the conventional ultrasonic delay line, no new unnecessary reflections occur; Since the second-order 1) coefficient, which was considered to be an unnecessary reflection, is used, the noise t(4) mixed into the output signal is significantly reduced, and a high-performance ultrasonic delay line can be obtained.

Furthermore, this ultrasonic delay line has a very simple structure in which one transducer element f16 is pasted on the glass delay medium 12 ('+jξ), so it has the effect of reducing manufacturing costs.

Next, FIG. 6 shows a block diagram of a circuit for ζ comb filtering using the ultrasonic delay line constructed as described above.

This comb-shaped filter was previously proposed by the applicant, and its configuration uses the same two terminals 16 and 17 for input and output.
One invitance element r19 is sold in series on the end r16 side of the ultrasonic delay line, which is carried out by f, and this i/
Betans 4+: l rl Both ☆;
l! f 3;) Manually add to circuit 22 (head height subtraction)
The output of the comb filter is taken out from this L11 circuit 22, and the same comb-shaped frequency/JJl number characteristic 1-1 can be obtained using the ultrasonic delay line with two ends r. It is.

Next, the ultrasonic delay line in another embodiment of the present invention is
This will be explained based on the diagram. In this embodiment, the conversion element 23 and the electrode 24 are
It is provided in the middle heat part of the end face 26 at.

When the ultrasonic delay line is configured in this way, the ultrasonic waves radiated from the left half of the transducer element f23 to the delay medium 25 are routed through the path 27.
& is propagated to the right half of the conversion element 23 by j! A, and if this ultrasonic wave is extracted, a delay (FF) with the same length of delay time as the conventional one can be obtained.

In addition, by eliminating the ultrasonic waves that are reflected by the end face 26, propagates through the path 27b, and returns to the conversion element 23, it is possible to obtain a delayed signal υ with twice the length of the sucking time compared to the conventional one. Selection of delay time becomes ijj function.

FIG. 7 shows a U1 wave delay line in yet another saturation example of the present invention. In this case, two conversion elements 292L and 29b are provided on the end face of the slow g fil' body 28, and these are electrically connected to 71 (pneumatically) by a lead wire, and one conversion element It serves as an element, and has 14 terminals as a whole. In this embodiment, the same effect as the first one-way flow side is achieved.

FIG. 8 shows still another embodiment of the present invention. Showing the voice wave delay line. In this case, the rod-shaped delay medium 30
One electric body 31a and 31b and one conversion element 32a and 32b are placed on both end faces of 0, respectively, and these are connected to 7if 'fiT,
It has a configuration in which the two ends are connected. This embodiment has the advantage that the ultrasonic delay line can be manufactured in an extremely small size and easily.

As explained above, the ultrasonic delay line L line of the present invention is used as a comb filter, and is small + +i
'f+I! You can get a long delay time with Jh function,
Moreover, it has the effect of being able to be installed at a low cost, and the actual market price is 111T.

[Brief explanation of drawings]

Figure 1 is a block diagram of a conventional comb filter circuit, Figure 2 is a diagram showing the frequency characteristics of a comb filter, Figure 3 is a front view of a conventional ultrasonic delay line, and Figure 4 is a diagram of the conventional comb filter circuit. A front view of an ultrasonic delay line in an embodiment of the invention, FIG. 5 is a block diagram of a comb-fill circuit using the ultrasonic delay line, and FIGS. 6 to 8 are other embodiments of the invention. It is a positive ini diagram of the ultrasonic delay line in FIG. 12.2'5T28.30... Delay medium, 13.
26...edge i, iii, 14 + 24 + 31
& + 31t) -・-・-7U%, j5,23.
29&, 29b, 32a, 32b・= conversion element r-0 Agent's name ↑ Physician Toshi Nakao and 1 other person Figure 1O Figure 4 If

Claims (1)

[Claims] A 71Σ1 moe and a conversion element are provided on the end face of the slow IL medium,
The ultrasonic wave emitted from the conversion element r- into the delay medium is
- An ultra-high wave delay line formed so as to return to the conversion element described in (2) after the violation in (1).