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JPS5357020

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DESCRIPTION JPS5357020
Description 11 Title of Invention
Receiving system
3. Detailed description of the invention The present invention also relates to a receiving system
having an insensitive property to a predetermined direction, in particular, a receiving system
adopting a cardioid type response property / microphone / array. Amateurs and true ssss who
have produced veterinarian vocalized films using conventional devices are well aware of the hard
work of reducing camera motion 11 to pick up on the shooter. If you can not reduce the camera
operation sound t you can pick up at the time of shooting @ 9, at the time of projection, the
original sound of the film may be hidden by the camera noise recorded at the time of shooting.
During this time, one way to solve the Thk is to separate the microphone and the camera 41
theoretically. However, in this method, the assistant is acclaimed at the same time as recording is
performed in accordance with shooting, and it is generally not an adequate method. Therefore, in
order to simultaneously perform recording and photographing by one person, a microphone is
usually attached at a position outside the body shadow field in front of the camera using an
extension member from the camera. In order to make it 1t- # corresponding to the scene, usually,
an inexpensive cardioid microphone can be fully effective by pointing the cardioid dead point to
the camera and attaching it to the camera by the above-mentioned method. However, the
frequency spectrum range of camera operation noise is wide, and even with the above method, a
considerable amount of noise is still recorded. The spectrum of the camera noise is about 6 from
the low frequency of about 100 Hz. It has been known empirically to have a beak close to 200
Hz, which extends up to OOO Hz and has a maximum hearing area of @KTo. Although K is often
sufficient with conventional low-cost cardioid microphones to eliminate low frequency noise
generated by the camera, the spatial characteristics of this ax microphone are that the relatively
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broad spectral axis of noise associated with the mechanical actuation of the camera It is not
constant with respect to the frequency over time. Therefore, the action sound of the camera is
superimposed on the child corresponding to the subject field, and the result is that the recording
can be made. And, since it is very close to the microphone as compared to the noise source or the
subject, most of t0 being t-g becomes camera noise. While it is possible to design a special
microphone with the ability to filter out camera noise over a fairly wide range of H, such
microphones become very expensive and the microphone boron is inherently fragile. Being
possessed, it is susceptible to mechanical damage. The object of the present invention is
therefore to provide a new, high-performance recording system characterized in that the
rejection characteristics for the incident angle and the frequency are determined by means of
signal processing rather than the mechanical content of the microphone elements. .
The receiving system of the present invention, which is insensitive to a predetermined direction
with respect to incident energy, comprises an array of receiving members, each receiving
member being sensitive to incident temporally variable energy, to that energy Output a
corresponding temporally variable signal. The receiving system further comprises a signal
processing device ? such that the output signal t of each receiving member is substantially
insensitive to its energy for a specific frequency and angle of incidence determined by the
spacing of the receiving members. I will. In the Gi processor, EndPage: generated from a pair of
receiving members: Addition channel / channel for obtaining a sum signal of 2 output signals,
and for obtaining a differential signal of output signals generated from a pair of receiving
members A subtraction device, an integration channel for obtaining the integration of the
difference signal, and a coupling device for combining the outputs of the two channels / s are
provided. The phase of the summation signal and that of the integration signal are equal to the
energy of an arbitrary frequency incident on the array, and the phases of both signals change
with time of the incident energy. As for vibration, the frequency and the predetermined incidence
are selected by selecting the gain t-brickly applied to these signals before subtraction operation
of both the signals and selecting the interval t-overcutting of each receiving member constituting
the array. It is possible to make the amplitudes St of both signals with respect to the angle equal.
Specifically, for low-frequency energy incident at a predetermined angle with respect to the array
axis (that is, the frequency of energy is close to zero), the gain is thin so that the signal
subtraction result value is zero! The relative gain of the lI signal is selected. In addition, the
spacing between each pair of receiving members is also selected so that the amplitudes of both
gain-adjusted signals are equal to the energy of any frequency incident at a predetermined angle
with respect to the array. When the receiving system of the present invention is used in a
cinematography system, the signal processing unit operates so that the receiving member array
acts as a cardioid microphone in the low frequency region, and in the frequency band that
occupies most of camera noise. In contrast, it exhibits perfect removal characteristics on the
cardioid axis. The movie shooting system and the camera recording system coupled to the
camera and the t-movie shooting system also have the present F! A can all be used. Such a
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recording system is fixed to the camera outside the field of view 1il @ of the camera and supports
an * i line array microphone array, which does not necessarily mean that it projects in the lower
front of the camera. Is preferred-.
The microphones are arranged such that the camera operation sound is preferentially removed
by the array during camera operation, and a signal processor is provided to combine the output
signals of the microphones. Low-frequency sound coming from an ax source along one direction
is removed to the same size as the kind of frequency that is most easily felt by the ear generated
from the camera. The recording system of the present invention is relatively simple and
inexpensive as described above, since all of the predetermined directional rejection
characteristics obtained by the present invention are based on the use of the signal processor
and the setting of the microphone spacing. It is possible to use a microphone. A description of
the preferred embodiment will now be given in contrast to the attached drawings. Referring to
FIG. 1, reference numeral 10 denotes a voiced movie system according to the invention
comprising a projection T11I photographing camera 11 and a recording system 12 connected to
the camera. The recording system 12 comprises a microphone 13 which is arranged in a row
with microphone elements (not shown) and is fixed to the camera 11 by means of a dome 14t
which together form one microphone. The recording system 12 is also provided with a signal
processor 15 which is connected to the camera via a cable 16. The camera 11 is provided with a
film housing No. 17 as usual, a film driving device (not shown), and a lens assembly 18, and the
photographic field light is in the camera housing via the lens assembly 18t. It is to be introduced
on film. A fanda 19 adjusted along the lens system optical axis of the camera is provided for
observing the field of the photographer. The camera is further provided with a Grino 7'20, and
the user holds the camera with one hand by holding the grip 20, and operates the camera by
operating the pull-type mold 21 'with one finger. , The other hand can support the camera stably.
The microphone elements of the serial arrangement constituting the microphone 13 are placed
on the X axis having a small angle (for example, 20 degrees) downward with respect to the
optical axis 2 in the plane including the optical axis 2 and the grid f 20 t ? In this manner, the
microphones 13 are fixed to the boom 14 in a state of being protruded to the lower front of the
camera, and the EndPage: 3 such that they do not enter the field of view of the lens assembly /
pre 18. When operating the camera, the user grips 20t with one hand, stabilizes the camera with
the other hand, and observes the field through the finder 19.
When the trigger is pulled, the camera and the microphone are activated to capture an object
within the field of view of the finder, and at the same time, the sound from the object is also
recorded. The microphones 13 are mounted in accordance with the direction of the dome 14 and
are positioned to sense ft-from the field. The microphone 13 has a cardioid response
characteristic (total characteristic by each microphone element) as described later. Its spatial
response as a function of frequency is determined by the signal processor 15. In essence, the
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microphone / 13 is sensitive to sound incident from within the camera 11t-included solid cone
with a solid angle (referred to as the removal cone), as hydraulically represented by the dashed
line 22 in FIG. Not shown. The angle of the X axis with respect to two axes and the distance from
the camera to the microphone are four points at the position of the microphone 13. The solid
angle of the removal cone The solid angle depends on the operation of the signal processing unit
15, and Can be selected within a wide range of angles so as to fall within the cone region. FIG. 1
shows microphone response characteristics 23.24 for two orthogonal planes, and it can be seen
that the response characteristics depend on the direction of the incident sound. Each is
symmetrical about the characteristic diagram Hx axis. Although this characteristic diagram is not
represented numerically, it shows typical characteristics of the microphone 13 for M consecutive
frequency bands. FIG. 2 is a numerical representation of the frequency distribution of noise
generated from a typical cinematographic camera. The noise due to the camera operation
contains a very low frequency component, and it is known from FIG. 2 that the human ear has a
large peak at around 2,00OOHz within the range of 4b Iji & ? frequency i at most. I'm sorry. The
highest frequency component of the noise due to the camera operation sharply decreases around
6, 00 Hz. Signal processing device 15t--more particularly than 1. It is possible to adjust the
response characteristics of the microphone 13 so that the camera's operation noise can be
selectively removed over a fairly wide frequency band, which is a single point above around
OOOHz. In FIG. 3, Ml, M2, M3 and M4 are elements of the phycrophone 13, and one plane
acoustic wave is used to explain the method of selectively changing the removal characteristics of
the microphones 1 and 3 by the signal processing apparatus of the present invention. The
interaction between T.30 and a serial array of the four microphone elements Ml, M2, M3, M4 is
illustrated. The combined microphone elements that facilitate the following analysis are shown
equally spaced on the X-axis, but they need not necessarily be equally spaced.
In the figure, the distance between the middle elements M1 and M2 is represented by a distance
d1, and the distance between the elements M1 and M4 at both ends is represented by a distance
IId2. To simplify the analysis, it is assumed that the spacing of elements M1, M2 is equal to the
spacing of elements M3, M ,. In addition, it is assumed that the frequency of the flat sine 1 * 30 is
? and is incident on the microphone element array. The propagation direction of ta is generally
directed from the positive direction of the X axis to the negative direction. That is, the sound
wave crosses the X axis at a midpoint 31 of the microphone element M2, M3 with an angle ?
with respect to the X axis. It propagates along the A axis. Taira Il! Since 1ItIIL changes like a
Japanese patent, the position of the wave at a certain moment is shown in FIG. The relative
amplitude on the X axis of ti at this instant is shown by chain gA32. The dashed line includes a Yaxis intersecting the X-axis, and is defined as an intersection of a plane perpendicular to a plane
defined by the X-axis and the A-axis and the plane fIBL. The Y axis is passing point 31'5r. The
amplitude of the wave 32 at any one point on xsl is that of the point f [the magnitude t of the
amplitude. The value measured along the distance fA axis between any two points on the flat l1il
technique and the value measured along the x axis along fc is related by the cosine of the
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incident angle ? of the plane wave. A friend & 30 waves t ? measured along the A axis.
Assuming that i blunt X0 and the above ? measured in the flat 33 defined by the X-Y axis. The
following relationship stands in between. EndPage: 4 (1) ?0--X. ? ? f where V is the plane
wave propagation velocity, fz ? ? /. ???? The taO propagation temperature is 344 tn / 8 @
C at a temperature 20 ░ C. elevation O (sea II). The period T0 of the plane wave is as follows. A
point 34 on the wave 30, which is a projection point on the middle point 31t-X axis of the
microphone element M3, is a point tx thin-axis projection point at a distance (1/2) dl from the
installation point 31 of the microphone element M3. It is apparent from equation 121 that the
time to move to point 35 is 1 (3) .tau..sub.1 wing-.intg..alpha..sub.v The time until point 34 of the
plane direction temporary tack reaches microphone combination M4 is. Equations (3) and (4) tConsidering the analytical waveform at point 31 taking account of it, analytically show the
waveforms at the four microphone element installation positions as relative phase difference
with the phase fixed waveform Can. That is, assuming that the waveform at point 31 is
represented by blood ? (t??0), the temporary positions at the installation positions of the four
microphones are represented by the following equation.
(5A) M1 at ?? (t??0 + ?2) (5B) M2 at ?2 (??0 + at 1) (5C) M at blood ? (??0?? ?)
(5D) M, ttk, m (t?? 0 ?? 2) where ? 0 is the propagation time during which the wave travels
a quarter of the time along the A temperature (thereby, the sine of the equation amplitude scale,
which will be described later, cosine) Can be used for any of Since any complex complex can be
synthesized using 7-rie sine series or 7-one rise cosine series, each equation in the analysis
described below is for a single sine wave of angular frequency- The analysis is of general
applicability. The details of the signal processing device 15 are shown in FIG. The microphone
elements M1 and M2 output time-varying signals according to their energy when given timevarying energy such as f-wave, and this signal is a block diagram of FIG. Processed in the order
shown. The signal processing device 15 includes not only microphone elements but also an adder
40 for adding output signals of the inner microphone elements M2 and M3 and a subtractor 41
for subtracting output signals of the outer microphone elements M1 and M4. The integration
channel 42 configured as an integrator integrates the difference signal generated from the
subtractor 41 and outputs the integrated signal as an integration signal. A signal processing
means is provided in the stone with a coupling device 43t for coupling the mass channel from
the summing channel and the integrating channel. This coupling device 43 has two gain control
devices t? for each channel 5 and channel 5, and the gain wA! The integrated signal subjected to
iiE and the gain-adjusted addition signal appearing at the output end of the amplifier 45 with
gain are generated, and these advantages are set so that 4A and B have a relative relationship as
described later. It is done. The combining unit 43 further comprises a summing unit for totaladding the two gain-adjusted signals in the upper half, which is illustrated as the summing unit
? -adder 46. The output of summer 46 appears on line 47, which is the output of microphone
13. Assuming that the inputs of the microphones M1 to M4 can be expressed by the expressions
(5) to (5B), the sum signal S appearing at the output end of the adder 40 is as follows. EndPage: 5
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? ^ On the other hand, the difference signal appearing at the output end of the subtractor 41 is
as follows. The negative sign indicates that the differential signal is out of phase with the sum
signal.
When the differential signal is integrated in the integrator 42, an integrated signal signal given
by the following equation is obtained. That is, an integral value I 'of an arbitrary time t to t ?
includes a sine wave component (first term) and a constant term (second term) ?. Therefore,
taking out the sine tR acid component by AC coupling and making it an integrated signal,
EndPage: 6 Therefore, the sum signal and the integrated signal both have the same frequency
and the same phase, regardless of the value of ?0. Sum signal 8 has gain m by amplifier 45 & c.
I, its amplitude A (#, &) is 191A ("* ?) = person О 20-? 1-2 person 0-? 1 Also, the integrated
signal is gain-adjusted by the amplifier 44 and its amplitude g (" s ? ) Is given by the following
equation. It can be understood that the output of the adder 46 can be a tail, considering from the
formula (2):-(41, ff) w (-1?) + B (?t??) @. That is, by selecting the relative gain person / B of
the gain-adjusted signal and the distance between microphone elements 111k (l, d2 and tproperly select any frequency of the incident wave to the microphone accumulation array For the
angle of incidence, it is shown that the complete removal of the incident wave is possible. For low
frequency incident tlLK where ? is close to zero, ? ? becomes K as follows. From the equation
(12), it can be understood that the output of the adder 46 is zero when the parenthesis is an eport. Arbitrary incidence angle ?. The relative gain A / B of the gain-tuned signal to obtain
perfect-pass at low frequencies is Substituting the relative gain of equation (12B) into equation
(6), the incident angle ? with respect to the microphone element array 9. The following general
equation for the output of the adder 46 is obtained to preserve low frequency rejection with.
EndPage: 7 In order to remove the low frequency incident on the microphone element array at
the incident angle ?olI + lIO, the equation (d) is as follows. As apparent from the equation (13A),
the signal from each microphone is geographically distributed as described above, and it has a
cardioid response characteristic with one axis of symmetry (ie, X axis) and T axis (i.e., X axis). It
has a monotonically increasing characteristic. The high frequency characteristics of the
composite microphone with respect to the energy incident in parallel to the array t are as follows
from the equation (d) with ? = 0. The distance dl between the microphone elements provided to
obtain the combined g-polarization can be selected so as to be guaranteed for the elimination of
the technique of any frequency ?, incident angle ?. Such dlot can be obtained from an equation
in which the parentheses in the equation are zero, and K is as follows.
When removal with respect to the frequency incident from the positive direction of the X-axis is
obtained in the serial micro-mirror 7 array on the X-axis, ?-to dl are as follows as ?1 = ??.
FIG. 5 is a graph of the equation (13A), which is expressed as a function of the low mesh
characteristic t of the microphone element array when the output of the microphone boron is
processed according to FIG. It is a thing. In this way, the serial array, which is an omnidirectional
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receiver with a built-in microphone, changes to a composite microphone having a cardioid
characteristic by adopting signal processing t by the signal processing device 15. If each
microphone has its own or cardioid characteristics, synthetic microbons will have even better
cardioid characteristics due to signal processing. The characteristics of the micro / boron array
for relatively high frequency tears incident on the microphone boron array along the array (ie ?
= 0) are shown at the sixth factor, which is shown in equation (13B) It was created based on that.
The curve 50 is a gain-adjusted integrated signal which appears at the output end of (8, 44). It
should be noted here that in the case of d '= d2, elements M and M2, M3 and M4 are respectively
combined to constitute a 24 accumulation microphone, rather than four microphone elements
being combined. It is. Such a microphone has good low frequency rejection but its rejection for
relatively high frequencies drops steadily with increasing frequency as curve 52 shows. This
curve 52 is the difference of the curve 50.51 and represents the equation (13B), that is, the
output of the adder 46. The microphone element of A curve representing a cm (") in this state 6
Lv at one curved edge 53 This curve 53 approximates the curve 51. The curve 54 is the
difference of the curve 51.53, and it is clear that at 41 in the condition d ?; d2, the elementary
synthesis microphone has an improved removal characteristic for dogs compared to a twoelement synthetic microphone. FIG. 6 is provided with a frequency scale in the case of d2-25.4 m
(l-y +) data, and v is zero. If the wave incident along the array belongs to 6,000 J (camera noise
region up to z, the ratio of dl and d2 should be properly selected to improve the removal
characteristic 'kl etc. for that wave Is possible. Here, dl is chosen so that the gain-adjusted sum
signal (ie the frequency of the cosine curve) at a frequency of about 69% of the gain wAa
integrated signal is biased towards the gain-adjusted integration signal (ie the sine curve)
Preferred, this condition is d2 = 25.4. (L (yf) O and 1 !, 8.0 OOHz are satisfied, dl electric 14wm
(0.55 inch) is obtained from the equation (14 persons).
Curve 60 in FIG. 6 represents the gain-adjusted sum signal in the above condition, curve 61
represents the gain-adjusted integrated signal, and these two curves a8. They are equal to each
other in OOOHz. The difference between the curves 60.61, ie the output 47t of the adder 46-s,
ooog, as the curve 62 represents. The removal characteristics in the following frequency bands
are very good. Each curve in the figure is applied to the input wave parallel to the array. The gs
diagram and the 8149 diagram respectively show the removal characteristics at an incident
angle of 30i 60 degrees. In FIG. 8, curve 63 represents the gain-adjusted sum signal at .alpha.50.degree., And curve 64 represents the integrated signal t with gain m adjusted f. Curve 65
represents the difference t-of curve 63 ░ 64. In FIG. 9, the gain-trained apparent signal is
represented when the curve ? is ? = 60 ░, and the curve 61 represents the gain-adjusted
integrated signal. Curve 68 represents the difference between curves 66.67. Given that dl = 14
(0,55 inches), d2 ? 25,4 (1 inch), from ? = 0 ░ to ? = 500 (TJ (corresponding to a 60 ░
corner removal cone) It is clear that very good removal characteristics are obtained in the range.
By selecting the relative gain of the addition channel and the integration channel excessively and
selecting the pair to be subjected to the addition processing of the microphone accumulation and
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the pair to be subjected to the subtraction processing to the pair of mutual spacing t?a, the
other removal characteristics are obtained. It is possible to get. In addition, when the Microkhoff
convolution is placed at an unbalance interval, analysis results different from the above are
obtained. Although the above B5e light was performed based on the whole relationship between
the number of sounds and the microphone, the present invention is also applicable to the case
where an element of the right is sensitive to an energy other than f & and an output signal is
generated. It is clear. For example, it is possible to use the present invention for the connection
between a telephone and a receiving antenna. FIG. 10 is a circuit diagram EndPage: 9 of the fC
signal processor constructed in accordance with the present invention to obtain arbitrary signal
rejection characteristics. A signal processor (15A) q4 microphone elements M1 to M4 and a
preamplifier TO coupled to each element one by one are provided. The output signals of the
microphones XM2 and M3 are amplified by the preamplifier 70 and then added by the analog
adder 71 to form a sum signal. The output signals of the microphone elements M1 and M4 are
amplified by the pre-amplifier 70 and then subtracted and integrated in the two-tone differential
integrator 72 to appear as an integrated signal.
The above sum signal and integrated signal are added in the analog adder 73 to become an
output signal. Various changes and modifications can be made to the present invention without
departing from the features and advantages of the method and apparatus according to the
present invention.
4. Brief Description of the Drawings FIG. 1 is a perspective view of a movie camera embodying
the present invention, and a symmetry low-resolution cardioid characteristic diagram of the
movie camera, and FIG. 2 is a typical noise spectrum associated with the movie camera. Graph
showing numerically in gold, Fig. 3 is a perspective view of a linear array (a perspective view of a
one-member array, showing a plane wave having an arbitrary frequency and an arbitrary
incident angle gold incident on the array, Fig. 4 FIG. 5 is a block diagram of a receiving system
according to the invention, a block diagram of a signal processing device, FIG. 5 being a pole
point of the response characteristic of the receiving system according to the invention with
respect to a specific relative gain between summing and integrating channels for low frequency
energy. FIG. 6 is a graph of the respective amplitudes of the sum signal and the integral signal in
the system of FIG. In addition, in the case of the double, the addition to the energy incidence
along the array axis, the graph showing the shadow 41 ? ? ? ? to the displacement of the fi @
of the integrator channel, and FIG. 7 is a view similar to FIG. , A graph showing the case where
the microphone pair spacing is selected so that the amplitude difference of the summing and
integrator channels becomes zero with respect to predetermined AC energy entering the array, #!
Figure 8 shows the amplitude of the sum and integrated signal with respect to the energy
incident on the array at an angle of about 30 degrees St--A graph similar to Figure 1 and Figure 9
a graph similar to Figure 8, at an angle of about 60 degrees FIG. 10 is a graph showing the
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situation when energy is incident on the array, and FIG. 10 is a block diagram when a signal
processing apparatus suitable for implementing the signal processing method of the present
invention is applied to the four microphone element configuration of the present invention.
(Explanation of the code) Ml, M2% M311 M4 иии Microphone ииииииииииииииииииииииииииииииииииииииииииии ..... recording
system 13 ....................... microphone 14 ....................... microphone mounted boom 15
ииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииии ........... Adder
41 ................ Subtractor 42 .......... Integrator 43
ииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииии .. Adder agent
Asamura Yuuka 3 people EndPag : ??
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