close

Вход

Забыли?

вход по аккаунту

?

JPS53112701

код для вставкиСкачать
Patent Translate
Powered by EPO and Google
Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JPS53112701
Specification L Title of Invention
Booming remover
DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for
eliminating zooming that occurs when a speaker emits a single sound in a room. In particular,
according to the condition of the room, the frequency component that causes seaming from the
signal supplied to the speaker in advance is extracted by a simple operation. When listening to
music etc. in a room of relatively small volume surrounded by a hard wall, the sound of a specific
low-pitched range may be distractingly and sometimes cause discomfort. Such a phenomenon is
known as zooming. For example, when the speaker of the stereo device is sounding in a room of
a general house, the frequency characteristic of the signal supplied to the speaker or the sound
from the speaker is flat even as shown by the solid line in FIG. The frequency characteristics of
the sound finally reaching the listener are as shown by the solid line in Fig. 1 because the
reflections from the ceiling, wall, floor, etc. of the room are complex reflections and innumerable
reflections overlap each other. There are many mountain valleys. The booming is a phenomenon
in which the beaks are heard in a perceptually audible manner due to the sparse occurrence of
the beaks P1% P2 and P3 which appear in a low frequency band, for example, among the
mountains and valleys. Also, zooming generally occurs for a plurality of frequencies ('x sr, fs...)
Specific to the room in the range of approximately 6 ° to 200 Hz. Such booming not only causes
discomfort but also has an adverse effect that high-level bass masks middle and high-pitched
sound and significantly impairs the sound quality. Traditionally, architectural and acoustic
methods and electrical methods have been attempted to eliminate such seaming. As the former
method, it is known to suppress seaming by applying sound absorption processing indoors to
EndPage: 1, but since it is technically difficult and time-consuming and expensive, it is especially
08-05-2019
1
practiced in general houses as a seaming measure. There are very few examples. In the latter
method, for example, it is performed in a hall, a monitor room, etc. to make the input signal of
the speaker have a specific frequency characteristic using graphic equalization or the like, and
thereby correct the characteristic of the sound field. We have been tried in the general sunning
room. However, although this method is often used by dividing the audio reproduction band into
one octazo band as graphic equalization, the center frequency of each band is fixed and the filter
band is wide, so as a measure against shimming. If used, the predetermined seaming frequency
suitable for the condition of one room can not be removed, and there is also a drawback that the
portion of the low band which is not necessary to be removed is removed to make it feel that the
bass is lacking.
In addition to this method Lj, not only graphic equalization but also various measuring
instruments are required, and their handling requires specialized knowledge, and so on. In
general, the present invention has been made in view of the above situation. A filter having
attenuation characteristics and capable of changing its center frequency is provided in the sound
reproduction system, and the output of the variable frequency oscillator is applied to the speaker
through the filter. Hereinafter, an embodiment in which the present invention is applied to a twochannel stereo reproduction apparatus will be described with reference to the drawings. The
boomk removing device (1) according to the present invention shown in FIG. 2 is used by being
connected between, for example, a preamplifier and a main amplifier of a sound reproduction
system. By this zooming removal device (1), the frequency characteristics of the input signal of
the speaker shown in FIG. 1 ^ are provided with dips Dl, D, and 8 of the frequency f1s'hf3 as
shown by the dotted line in advance. C) Beak P which is the number of seaming occurrence
shown in! , P, and P are removed to obtain characteristics as shown by dotted lines. The
shimming removing device (1) is constituted by a circuit system of an L channel system (2) and
an R channel system (3)], and each channel system (2) (3) has an input terminal (4) (5) It has an
output terminal (6) (7>). s、sS2はチューニングスイッチ、S3はLチャンネルチューニング
ONスイッチ、S4はRチャンネルチューニングONスイッチ。 5s1s is an on / off switch of the
seaming removing device (1). (8) is a frequency variable sine wave signal oscillator, for example,
a voltage controlled oscillator (VCO) is used, and its oscillation frequency is continuously
changed in a range of 25 to 400 Hz, for example. (9) is an amplifier, and OQ is a frequency
detector, which outputs a detection voltage V according to the output frequency of the oscillator
(8). Among these, this frequency detector (9) may be configured to use the oscillation frequency
control voltage when the oscillator (8) is configured by vCO, and may be configured by another
station wave number discriminator or the like. Next, in the L channel system (2), a filter for
extracting a frequency component causing booming from a signal supplied to a speaker (not
shown) from 0υa 2 (L L 1) is connected in series via a switch 87.8 sl Se. These filters 0υ @ 0
are composed of a contract notch filter having an ultra-narrow band elimination characteristic as
shown in FIG. The range is variable.
08-05-2019
2
In the embodiment, three filters 0 @@ are used, but the number of filters may be increased as
needed. α ◆ is a filter selection device, and is constituted by a reference power supply 05 曽, Q
(G), α 翰, a comparator μI and a frequency detector 発 生 generating M '441 under pressure Vr,
1VH4, VL2VH2, VL3VHf, respectively. ing. This filter selection device (b) is for selecting and
displaying which of the filters l and 1'1) @. Alpha. 鱒 is a filter tuning device, according to buffer
amplifier 111145) & s 7) s rectification smoothing circuit @ n @, to comparator (c)) and
reference power supply (jj) 2 generating reference voltage vls V 2 s 3 respectively System is
configured. This filter tuning device @ is for changing the center frequency of the filter 1 selected
by the filter selection device .alpha. And displaying the same when it matches the seaming
frequency. (B) is a display device with a flashing signal generator-, a gate (A071s IA0! J, f 4 G
(4υ and n nz, light emitting diodes, etc., ht A “End Page: 2 light emitting elements (4 z <43
(more than 4 J. The R channel system (3) is also configured the same as the JL channel system
(2) by the three filters, the filter selection device, the filter, and the filter. The oscillator (8), the
amplifier (9) and the frequency detector αQ are shared by both channel systems (2) and (3).
Next, the filter Q rod l will be described. For example, a notch filter as shown in FIG. 14 is used as
the filter 0p (2) a3. This notch filter has a circuit configuration called NULL network (NULLNHTO
几 K) formed by bridge-connecting a variable resistor tj: j (49) (50) s resistor G 〃 and a variable
capacitor 6 よ う as shown. It is possessed. By adding the input signal to the q input and the
terminal [A], an output having an ultra-narrow band attenuation characteristic at the center
frequency fo as shown in FIG. 3 can be obtained at the system output terminal WSa. The
determination of the center frequency of each filter, the removal band and the removal level will
now be described. Determination of the center frequency (a), zooming is the peak of the
transmission characteristics due to the isolated ‒ with vibration · of the bass range, but with the
frequency 1 'number, the beam occurring in the range of approximately 60 to 2.00 Hz The peaks
that are involved and that occur outside the above range are different from the phenomenon
called zooming.
(B) When the notch filter is constituted by the circuit as shown in FIG. It becomes difficult to
maintain the balance between the elements and to stabilize the characteristics. (C), isolated
natural vibration modes in a room may exist close to and separated from one another. The center
frequency variable range, which can be considered as the booming removable range for reasons
(a), (b) and (C) above, is given 30 to 240 H2 with some margin at the upper and lower limits, and
this range is three filters We share in Q υ 0 躇 (ha). That is, as shown in FIG. 5, the center
frequency fol of the filter Q1) is continuously variable in the range of 30 to 100 Hz, and the
center frequency foz of the filter @ is continuously variable in the range of 60 to 16.0 H2, The
Noh frequency fo3 of the filter o3 is variable in the range of 120 to 240 H2. In the case of 6, the
range of 60 to 1'60 H1 where zooming is particularly likely to occur is covered by three filters
0υ @ a3. The determination of the in-band (a), the station detection rate due to the auditory
sense of the valley characteristics present in the transmission characteristics, is generally for the
08-05-2019
3
increase of the overall bandwidth of the reproduction range, the decrease of the valley
bandwidth, the increase of the valley center frequency, etc. Tend to be lower. Therefore, it is
preferable to reduce the bandwidth of the filter as much as possible within the range necessary
for the removal of noise and noise from the point of improving the sound quality of the bass. (B)
On the other hand, the resonance sharpening of the natural vibration mode in the room which
becomes zooming is inversely proportional to the damping constant of the mode. Therefore, the
resonance taste becomes gentler as the sound absorption power in the lower region becomes
larger. (C) A natural vibration mode in a rectangular parallelepiped room may occur in a
concentrated manner in a narrow frequency range, and in this case, it is lower than the bass limit
frequency where the natural vibration mode may exist in isolation. Even at the frequency, there is
a series of resonance tastes, and there is a resonance taste with apparently low resonance acuity.
For the reasons of the above (a), (b) and (C), the removal bandwidth B of the filter Qυ (la03 is
variable in stages, for example, in six stages from narrow to wide. The reason for not making it
continuously variable is that the removal bandwidth in the zooming removal does not need to be
adjusted so strictly and to maintain the stability of the circuit. The removal level is continuously
variable in the range of 0 to -30 dB in each filter 0 eta o 2 alpha field. The removal level
changing method will be described in more detail later. Next, the operation of the apparatus for
removing the booming C34 configured as described above will be described in detail later
according to the description below, and the outline will be described here.
In FIG. 2, first, the switches s1s, sss, S, S8S, and S3 are turned on, and the switch S4 is turned off
to bring it into the illustrated state. Next, the oscillator (8) is operated to gradually increase the
oscillation frequency continuously from around 30 Hz (or lower from around 2 SQ Hz). This
oscillation output is amplified by the amplifier (9), then passed through the switch S through the
switch S1, through the switch S1, through the switch S7, the filter (2), the switch S8, the filter (s),
the switch S9 and It is switched to the output terminal (6) through the switch SIl, and is further
added to the speaker through the main amplifier (not shown). This causes the loudspeaker to
radiate into the sound room at the above-mentioned oscillation frequency. When the oscillation
frequency is increased while listening to the sound from the speaker, seaming occurs at a
frequency f, for example. At this time, the oscillation frequency adjustment knob of the oscillator
(8) is fixed at fl. On the other hand, the above oscillation frequency is detected by the frequency
detector 0θ, and based on this detection voltage, the filter selection device a4 is controlled by
the oscillator (the current oscillation frequency of 8n is within the variable range of each central
frequency '01sfORs' <13 shown in FIG. It is determined which of the ranges is within the range
which can be covered by the filter IJJ) E (13). A light emitting element t4 ';! J: One or two of 43
(44) emit light and a filter that can be covered is displayed. As a result, when zooming occurs at
the frequency f1, it is possible to determine which one of the filters a @@ (2) should be used to
eliminate the signal of the frequency f. Now the frequency f! When the booming occurs at the
light emitting element (in this case, the filter 0 is used if the light emitting element 424 is in
charge. The selected filter CI is then manipulated to change its center frequency fol. Then, when
08-05-2019
4
fol matches with f, the filter tuning device (c) is operated, and the light emission of the light
emitting element (42 disappears. As a result, it is determined that the fol and 4 match, and the
frequency f! Fix the In this state, the filter Q is operated to adjust the removal level at the
frequency f1 and in the band so that no seaming occurs and the aurally most preferable state is
obtained. After that, the oscillator (8) is operated again to increase its oscillation frequency from
fl. Then, seaming occurs at the frequency afs, and at this time, when the light emitting element
(43 emits light and the filter (6) is selected), the center frequency fo3 is changed until the light
emitting element (4 & 's light emission disappears, removal level And adjust the inside of the
band appropriately.
Next, similarly, if seaming occurs at the frequency f3 and the light emitting element tA41 emits
light, the filter (c) is used to adjust the center frequency fo, the removal level and the inside of the
band by the same operation as described above. Since the cover range of the filter α フ ィ ル タ
@ (2) overlaps each other as shown in FIG. 5, two of the light emitting elements (421 (43 (44))
simultaneously emit light when seaming occurs. In some cases, either of the two corresponding
filters may be used. Furthermore, when seaming occurs twice in the above-described portion, the
two filters may be shared to remove those two seaming frequency components. Also, by setting
switch Bq, Sm or 87 to S9 in advance to change the oscillation frequency from the minimum to
the maximum (or from the maximum to the minimum), it is necessary to know the approximate
frequency at which zooming occurs in advance. You may make it adjust by performing operation.
As described above, the adjustment of the 9 L channel system (2) is completed, and then the
switch S3 is turned off and the switch S4 is turned on to adjust the 調整 channel system (3) in the
same manner. When the adjustment of both channel systems (2) and (3) is completed, the switch
SIS is turned off to add an audio signal to the input terminals (4) and (5) from a signal source
such as a record player or tape recorder via a preamplifier. As a result, the sound reproduction
system can have the transmission characteristics as shown by the dotted line in FIG. 1 ', thus
eliminating the occurrence of seaming at the frequency' 1s'2s'3. Next, the filter selection device a
<will be described. In FIG. 2, the frequency detector α outputs a detection voltage V according to
the oscillation frequency of the oscillator (8), and this detection voltage V is a comparator anwc!
It is applied to one of the three input terminals. At the other input terminal of the comparator (2),
a voltage MHI equal to the detection voltage V when the excavation frequency reaches the upper
limit i wave number of 100 Hz of the cover range of the filter Q is applied from the reference
power supply (c) A voltage VLI equal to the detection voltage V when the oscillation frequency
reaches the lower limit frequency of 30 Hz of the cover range of the filter a is applied to the
reference power supply). As a result, as shown in FIG. 6, when the oscillation frequency is
between 3 ° EndPage: 4 to 100 H2, that is, when vLt <V <VH □, an output signal of a low level
is obtained. A high level signal is obtained by the output signal when the oscillation frequency is
out of the above range, that is, when the oscillation frequency is out of the above range, that is,
when The 3 'is closed.
08-05-2019
5
Also, comparator C? Voltages VH and V and VIEflVL1 corresponding to the upper limit and lower
limit frequency of each force / mer range of the filter (2) a3 are respectively applied to the other
input terminals of 4Q3 based on the same concept as described above. As a result, when the
oscillation frequency is in the range of i <6 o to 160 Hz, that is, in the case of VL2 <V <VHt, a low
level output signal as shown in FIG. With the signal, the signal ttl is opened, and when the
oscillation frequency is out of the above range, that is, when V <V, and V) VH2, a high level signal
is obtained, whereby the data (3!! 1 is closed. Similarly, when the oscillation frequency is
between 120 and 240 H2, that is, when L3 <V <? Us, a low level output signal as shown in FIG.
6C) is obtained as shown in FIG. When the oscillation frequency falls out of the above range, that
is, when V <VL3 and V> V, a high level signal is obtained by the signal r ′ ′ − t (qυ−),
whereby r−t r It is closed. Next, the operation according to the above configuration will be
described. In the initial state, the date of the display device (b) (clock (41) is open and key-) (31
(19 (four is closed), light emitting element !, +21! 43 (441 is off. In this state, the oscillator
frequency is increased by operating the oscillator (as described above). When the oscillation
frequency exceeds 30 Hz, a low level output signal is applied to the gate 37 by comparing the
detector 5v of the frequency detector QO with the reference voltage VLI. As a result, the flashing
signal generator (blinking signal from 39 is added to the light emitting element (Q) through the
gate (36137), and the bamboo light emitting element (42i emits flashing light in a cycle of 40
m8, for example). When the oscillation frequency is further raised and exceeds 100H2, the
output signal of the comparator Qυ becomes high level, the gate 07 is closed, and the light
emission of the light emitting element 4δ disappears. According to the above, it is understood
that when the booming occurs between the above 30 and 100H 20, the booming can be removed
by using the filter θ 素 子 because four light emitting elements emit light. In the same manner as
described above, when the oscillation frequency is in the range of 60 to 160 Hz or 120 to 240
Hz, the cover 0 extension or (41) is opened and the light emitting element (4 or 14) blinks, If
booming occurs in these ranges, it can be seen that the booming can be removed using the filter
(6) or a. This filter selection device (b) can be applied to other than the dimming removal device.
That is, for example, in a transmission system having a plurality of band pass filters different in
frequency band from one another, when it is intended to change the characteristics of the
respective band pass filters to give the frequency characteristic of the whole system, a sine wave
signal is usually input. In addition, the output is monitored by changing its frequency. In this
case, in order to determine which band-pass filter should be adjusted, the frequency of the input
sine wave is determined by measuring with a frequency counter. The operation as described
above requires various measuring instruments and requires specialized knowledge. In such a
case, the band pass filter to be adjusted can be easily selected by displaying it with, for example,
a light emitting element or the like using the filter selection device α ◆. Further, in addition to
the filter having the ultra narrow band removal characteristic as shown in FIG. 3, this filter
selection device a has a filter having the ultra narrow band pass characteristic, a normal band
08-05-2019
6
variable removal characteristic or a retrogression characteristic. It is possible to apply filters
having various characteristics as shown in FIG. 10 a, b, c% d. Next, the filter tuning device (c) will
be described. In FIG. 2, a part of the output of the filter g.eta. Is equal to the DC voltage VBI in the
rectifying and smoothing circuit (A) through the buffer amplifier (451), and the DC voltage VBI is
applied to one input terminal of the comparator (HA). . Reference voltage (3) is applied to the
other input terminal of the comparator (3). When VBI <Vt, a low level signal is output from this
comparator (c), and the gate (d) is closed by this signal. Similarly, a part of the output of the filter
020: f) is rectified and smoothed through the buffer EndPage: 5 amp (f3 (46) (h) (b) DC voltage
VB !, v83), this DC voltage V82, VBS is They are respectively applied to one input terminal of the
comparator (e). The other input terminal of these comparators-is supplied with a reference power
supply az + 槙 and a reference voltage 焉, v3 respectively. Then, when VBt <Vz and VBs <Vs,
signals of low level are outputted from these comparators, and the signal t3s (40) is closed by
this signal. Next, the operation according to the above configuration will be described. Now, it is
assumed that the booming occurs at the frequency f1 when the light emitting element (42 is
emitting light) as described above because the oscillation frequency of the oscillator (8) is
between 30 and 100 Hz and the display device a4). Therefore, the oscillation frequency is fixed
to fl, and the central frequency fo1 is changed by operating the filter αη.
While fOl and fl are shifted, the output level of the filter? 'is large but the output level is
minimized when%' f (when 11 and fl coincide with each other). This output is applied to the
rectifying and smoothing circuit (c) through the buffer amplifier (451), and the rectified voltage
VBI is compared with the reference voltage {circle over (1)} in the comparator (c). And the signal
that it became fOl-fl is output, and date C 閉 is closed by this. As a result, since the flashing signal
of the flashing signal generator Oω is blocked by this gate operation, the light emission of the
light emitting element (l is extinguished, and it is displayed that the central frequency f61 of the
filter Oη matches the zooming frequency fl. After that, the oscillation frequency of the oscillator
(8) is increased again, for example, the light emitting element -F emitting light when booming
occurs at f2 or f: a filter corresponding to <a or (44) or (3) or a3 The central frequency fog or fo8
may be changed until the light emission of the light emitting element (43 or (44) disappears by
performing the same operation as described above. Although one light emitting element is
provided for one filter in the embodiment of FIG. 2, it may be provided for each filter in pairs □,-.
In this case, the blinking signal may be directly applied to r-) (i) (41) and the output of the (36) G
cap 41 may be applied to three separately provided light emitting elements. In addition to the
filter having the ultra narrow band removal characteristic as shown in FIG. 3, the filter tuning
device 3 has a filter having the ultra narrow band pass characteristic and a normal band variable
removal characteristic or the pass characteristic. Filters having various characteristics as shown
in a, b, c and d can be applied. Next, a method of changing the removal level of the filter Qυ @@
will be described. When a notch filter having the characteristics shown in FIG. 3 and the
configuration shown in FIG. 4 is used as the filter aD (2), the central frequency f · and the band B
constitute a circuit. By adjusting the size of each element, they can be varied substantially
08-05-2019
7
independently of each other. However, it is L in Figure 7 to remove it! If it is intended to change
continuously as indicated by ~ L6, characteristics which are not desired to be changed with the
change of the target removal level, such as the center frequency fO and the level LO of the pass
band, may also change. Also, the adjustment of such notch filters is subtle and it is extremely
difficult to obtain the desired removal level. The embodiments of FIGS. 8 and 9 can solve the
above problems.
FIG. 8 shows the principle, and the wedge is a notch filter having the ultra-narrow band rejection
characteristic of FIG. It is assumed that an input signal Vi including an Irmk frequency
component and a frequency characteristic of 72 bits is added to the input terminal. This input
signal Vi is applied to the notch filter (6υ and its output is applied to the adder-through the
attenuator domain. At the same time, the input signal Vi is applied to the adder through the
attenuator. The summed output of this adder is taken as the output signal 00 at the output
terminal-. In the above configuration, first, the removal level of the notch filter f61 is adjusted
and fixed to the maximum level L6 of FIG. Next, for example, the level of passage through the
attenuator is increased, and the output of the attenuator branch is reduced slightly by the
attenuator wheel to be added to the adder 、 and a flat on EndPage: 6 force signal The level is
greatly attenuated by Vi at the attenuator axis and added to the control unit. As a result, an
output signal Vn is obtained with the adder--the center frequency f and the components removed
at a level substantially lower than L6. Also, reduce the passage level of the attenuator. If you set
that of attenuator Q large. Contrary to the above, it is possible to obtain the center frequency f
and the output signal Vo removed at a high level close to L-. The attenuators NN are interlocked
in the reverse direction so that the levels L of the passbands other than the removal band are
always constant. FIG. 9 shows a specific embodiment which is exposed to the above principle,
and the parts corresponding to FIG. 8 are assigned the same reference numerals. In FIG. 9, the
attenuator (a) is composed of a resisting force, a variable resistance branch for feedback, and an
operational amplifier. The resistance value of the resistance Oη and the total resistance value of
the variable resistance-are equal and their magnitude is a bird. In addition, the movable terminal
of the variable paper sheet is a resistance value divided at 68 degrees. The attenuator Q has a
resistance of 0. It is composed of a feedback variable resistor (c) and an operational amplifier).
The resistance value of the resistor (d) and the total resistance value of the variable resistor (2)
are equal due to their size. Also, let the resistance value divided by the movable terminal (71a) of
the variable resistor (2) be “1 sk. The variable resistance-and the key a 'are interlocked in
opposite directions as shown in the figure. The adder C.fwdarw. Is composed of an arithmetic
amplifier). In the above configuration, each variable resistance... Therefore, the output level L6 in
the pass band of the circuit of FIG. 7 is equal to the input level L ·.
(However, it is assumed that the notch filter has no gain.) Also, since the output of the
operational amplifier (2) disappears in the removal band, the output applied to the buffer
08-05-2019
8
amplifier (c) 顛 (4η) is shown in FIG. In FIG. 9, it is taken out from between the notch filter Oη
and the attenuator wheel. According to the above, it is possible to change the removal level by
adjusting only <, variable resistance-(c), without touching the notch filter 6 itself. Further, the
removal level can be easily adjusted without affecting the center frequency fo1 bandwidth B and
the like, and the set value can be stably maintained. Furthermore, the configuration can be as
simple as adding two attenuators and one adder. In addition to the notch filter @ 〃, for example,
a filter having various characteristics as shown in FIG. 10 a, b% C 1 d can be applied to the circuit
of FIG. According to the booming apparatus according to the embodiment of FIG. 2 described
above, the following effects can be obtained. (1) The degree of booming and its frequency differ
depending on the room, and depending on the installation position of the speaker and the snning
point even in the same room, but the booming can be reliably removed correspondingly it can.
(2) Finding the Gominda frequency and adjusting the characteristics of the removing device (1)
according to the frequency can be performed by a simple operation and accurately by anyone
without using other measuring instruments and the like. (Since there are three Panonte filters,
there is no sense that the necessary bass is removed from the output as in the prior art, causing a
sense of bass deficiency. (4) The present device (1) can also be applied as a device for preventing
howling in a loudspeaker system having a microphone and a loudspeaker. In that case, the center
frequency of the filter is configured to be able to coincide with the frequency that causes
howling. According to the present invention, at least one filter having attenuation characteristics
and capable of changing the center frequency is provided between the signal source of the sound
reproduction system and the speaker, and the oscillation output of the frequency variable
oscillator is transmitted to the speaker through the filter. The invention relates to a boom
removing device characterized in that it is configured to be added. Therefore, according to the
present invention, it is possible to reliably remove the booming occurring at EndPage: 7 various
frequencies in accordance with the state of the room with a simple operation.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a frequency characteristic diagram for
explaining booming, FIG. 2 is a circuit diagram showing an embodiment of the present invention,
FIG. 3 is a characteristic diagram of a notch filter, FIG. 4 is a circuit diagram showing an example
of a notch filter, FIG. 5 is a principle circuit diagram of a level variable filter, FIG. 9 is a circuit
diagram showing an embodiment of a removal level variable filter, and FIG. It is a figure. Further,
in the reference numerals used in the drawings, (1) is a booming removing device, (8) is a
frequency variable oscillator, aQ is a frequency detector, Op @ α barrel is a filter, Q41 is a filter
selecting device, and (C) is a filter. The tuning family f, (34) is the display, and the trap of the
tuning is the notch filter. Agent Saturn Katsu Ii Han Tai Ku 0 Elephant EndPage: 85 Rev EndPage:
10 Warning: Page Discontinuities
08-05-2019
9
Документ
Категория
Без категории
Просмотров
0
Размер файла
25 Кб
Теги
jps53112701
1/--страниц
Пожаловаться на содержимое документа