JPS59122011A - Glass delay line - Google Patents

Abstract

PURPOSE:To obtain a glass delay line with spurious attenuation by fitting an input and an output transducer to the input and output surfaces of a glass delay line element with slight shift from their center parts. CONSTITUTION:The glass delay line is provided with the glass delay element 1 and the input and output transducers 2 and 3 fitted to the input and output surfaces 1a and 1b formed of both-side slanting surfaces of the element 1. The input and output transducers 2 and 3 are fitted slightly shifting from the center parts of both surfaces. Plural spurious absorbers 5 for specifying a beam spread of a signal are provided to both surfaces of the delay element 1 along paths of a normal signal converted into ultrasonic oscillation by the input transducer 2. Consequently, the largest spuriousness is attenuated to the amount of oscillation that an equipment, etc., require.

Description

[Detailed description of the invention] (Technical field of invention) The present invention relates to a glass delay line that is an ultrasonic delay line.

(Technical Background of the Invention) As shown in FIG. , input/output transformers 2 and 3 are installed.

As a delay line with such a configuration, the center frequency is 358 MHz.
, glass delay #! with spurious absorber 4 made of epoxy resin with delay time IH! A burst signal modulated at 2.58 MHz (the lower limit band for video equipment) is added to the input transducer 2 using
When the response from the output transducer 3 was examined, as shown in FIG. 2, spurious signals B and C due to the beam spread of the propagating ultrasonic signal were generated in addition to the normal signal output a.

(Problems with Background Art) By the way, video equipment and the like usually require a spurious attenuation amount of around -30 dB. However, one spurious C shows an attenuation amount of -34 dB, and the other spurious b shows an attenuation amount of only -22 dB. Therefore, spurious b appears as vertical stripes on the screen.

Therefore, in order to investigate the directivity of ultrasonic waves of the conventional glass delay line shown in FIG. 1, the present inventors set the delay r! of FIG. 1 as shown in FIG. The entire path of the normal signal and spurious signals B and C is shown by C paths A to C, and the test glass delay line, which is the same as the part surrounded by the frame in this developed diagram, is
It was prepared as shown in FIGS. 4A and B. The input transducer 5 on one end face of this test glass delay line was connected to 2°58 MHz, 3-58 MHz and 4.58 MHz.
When a burst signal modulated at MHz was applied and the responses from the six rows of output transducers on the other end were investigated, the results shown in FIG. 5 were obtained. That is, in this FIG. 5, the 15% and 20% positions indicate the positions corresponding to the respective passages B and C in FIG. In response to 2.
At 58 MHz, the attenuation amount was -17 dB and -26 ctn. Therefore, it can be seen that when a spurious absorber is provided in the test glass delay line, the values of -17 dB and -26 ctn become around -22 dB and -34 dB.

Based on the above, the inventors have determined that spurious paths B and C
(See Figure 3) When the radiation angles of (see Fig. 3) are made almost the same, if the positions of the input and output juicers are shifted, the amount of attenuation of the spurious C from the spurious path C decreases, but the spurious b from the spurious path B decreases. It was found that the attenuation amount of the two becomes larger and the directivity of both becomes equal.

(Object of the invention) An object of the invention is to provide a glass delay line with a large amount of spurious attenuation. Install the input/output juicer,
0 (Examples of the Invention) Examples of the present invention will be described below with reference to the drawings. Glass according to the present invention As shown in FIG. 6, the delay line consists of a glass delay element 1 and input/output surfaces 1a and lb consisting of sloped end faces on both sides of the element. It is equipped with an input juicer 2 and an output juicer 3.

The input/output transformers 2 and 3 are mounted on the output surfaces 1a and 1b, respectively, at positions slightly offset from the center thereof. In the illustrated example, these transducers 2 and 3 are both rb-t''n and t25.

Therefore, when the glass delay line of the present invention is developed along the path of the entire ultrasonic normal signal, this normal signal path is at a position of 2.5-n1 in FIG. 5 with respect to the conventional position. It will exist.

Input transformers 2 are installed on both sides of the glass delay element l.
A plurality of spurious absorbers 5 are provided along the path of the normal signal, which is converted into ultrasonic vibrations at the oscilloscope, for regulating the beam spread of one signal. The absorbent body 5 is
Since the normal signal path is shifted by 2.5n by shifting the output power reducers 2 and 3, n large and small rectangular and triangular shapes are formed to maintain this signal path.

Next, a burst signal modulated at 2.58 MHz was applied to the input transducer 2 of the glass delay line of the present invention, and the response from the output transducer 3 was examined.
As shown in FIG. 7, spurious signals b' and C' due to beam broadening were generated in addition to the normal signal output a'. However, since the path of these spurious b' and C' is located at approximately 17.5♂ in Fig. 5, and the directivity of both spurious are equal, the attenuation of the spurious c'iX was -30 dB, which was small. The spurious b' was -28 dB, which was an attenuation increase of 5 dB compared to the conventional one. Therefore, even if the glass delay line of the present invention is incorporated into video equipment, etc., vertical stripes will not appear on the screen.If the normal signal path is 2.5 dB, the normal signal output will be attenuated by 1 to 2 dB. However, this amount of attenuation can be ignored.

(Effects of the Invention) By installing the input/output transformer on the input/output plane of the N1DZ glass delay element at a position slightly shifted from the center of the N1DZ glass delay element according to the present invention, it is possible to eliminate the largest spurious output required by all devices. Therefore, when the glass delay line of the present invention is used in video equipment, excellent images without vertical stripes can be obtained.

[Brief explanation of the drawing]

Figure 1 is a front view of a conventional glass delay line, Figure 2 is a diagram showing the response output of the glass delay line in Figure 1, and Figure 3 is a developed view of the glass delay line shown in m1 along the regular signal path. , Figure 4A
SB is a front view and a side view of the test glass delay line, FIG. 5 is a diagram showing the output attenuation of the delay line in FIG. 4, FIG. 6 is a front view of the glass delay line according to the present invention, and FIG. FIG. 7 is a diagram showing the response output of the glass delay line of FIG. 6; l......-Glass delay element la...
......Input surface 1b......Output surface 2.3-...Transformer Z-F4.5...
・0 spurious absorber

Claims (1)

[Claims] A glass delay line having an input/output transete installed on each input/output side comprising an inclined end face of a glass delay element, the input/output transete.
A glass delay line is characterized in that the sensor is attached to the input/output side at a position slightly offset from the center of the glass delay line.