JPS63167512A - Filter adjusting device - Google Patents

Abstract

PURPOSE:To distinctly indicate feature parts in a synthetic characteristic to facilitate adjustment by switching and changing the characteristic of an optional filter of a circuit, where plural filters are connected in series, without having influence upon feature parts of the other filters. CONSTITUTION:A filter circuit 2 as the adjustment object consists of filters 2A and 2B connected in series, and respective circuit constants are changed in accordance with common filter adjusting data from a DA convertor 14 to change filter characteristics. At least one filter, for example, 2B can be switched and changed to considerably change the filter characteristic and the switched and changed frequency characteristic of the filter 2B is so set that the influence upon feature parts such as a peak and a dip or cut-off point of the frequency characteristic of the other filter 2A is reduced.

Description

[Detailed description of the invention] The present invention will be explained in the following order.

A. Field of industrial application B1 Overview of the invention C1 Prior art 0 Problems to be solved by the invention E 0 Means for solving the problems F 0 Effects G Embodiment G-1 Structure of one embodiment and Operation (Fig. 1.2) G-2
, Explanation of Bi-Od filter (Figure 3.4) G-3, Filter switching change (Figures 5 to 8) G-4, Specific example of filter adjustment (Figure 9.10) G-5, Others Embodiments (Figs. 11-15) H1 Effects of the invention A, Industrial field of application The present invention relates to a filter adjustment device, and particularly for adjusting a filter circuit in which two or more filters are connected in series. The present invention relates to a filter adjustment device.

B1 Summary of the Invention The present invention provides a filter adjustment device for adjusting a filter circuit formed by connecting at least two series-connected filters whose filter characteristics can be adjusted by changing circuit constants etc. to a desired optimum characteristic. By making it possible to change the characteristics of a filter to one that does not affect the characteristics of other filters, and by changing the filter characteristics during filter adjustment, the characteristics of the filter circuit output can be clarified and filter adjustment can be made. It facilitates the

C1 Prior Art Generally, in the process of checking electronic circuits, etc., it is necessary to adjust the peak frequency, dip frequency, cutoff frequency, etc. of a filter circuit to a predetermined target value. In particular, in circuits formed within analog integrated circuits (ICs), the relative ratios of the rated values of transistors, resistors, capacitors, etc. can be relatively accurate, but the absolute values are
Since the value varies from C to C, the above adjustment is indispensable for filter circuits that require high accuracy.

This filter adjustment is performed by detecting the filter output while continuously changing the frequency of the input No. 13 to the filter (so-called sweep) to -4a, and detecting peaks and dips on the frequency characteristic curve, or the power This is done by finding a characteristic part of the filter characteristic, such as a point, and changing the filter characteristic so that its frequency matches a predetermined target value.

B9 Problem to be Solved by the Invention By the way, when adjusting the cutoff frequency, peak frequency, dip frequency, etc. of a filter circuit formed by connecting a plurality of filters in series, the frequency characteristics of the filter series circuit must be adjusted individually. Since it appears as a composite characteristic of each filter, it is difficult to confirm the characteristic parts of the filter characteristics such as the peak, dip, cutoff point, etc.

In addition, especially in the case of a filter series circuit provided in an integrated circuit (IC), adjustment of each individual filter is often performed simultaneously using a common adjustment control signal, and each filter is Since the frequency characteristics of the filters change simultaneously, the composite characteristics of these frequency characteristics change in a complicated manner, making it even more difficult to confirm the characteristic portions of the filter characteristics such as the peaks. If it becomes difficult to confirm the characteristic portion of the filter characteristics in this way, the filter adjustment of 1.7 degrees will deteriorate, and the effort and time required for adjustment will increase, which is not preferable.

The present invention has been made in view of the above-mentioned circumstances, and uses a simple configuration to reduce the peak on the filter frequency characteristic curve.
The purpose of the present invention is to provide a filter adjustment device that facilitates confirmation of characteristic portions such as dips and cutoff points, provides high adjustment accuracy, and requires short adjustment time.

Means for Solving the E1 Problem In order to solve the above-mentioned problem, the filter adjustment device according to the present invention comprises at least two filters that can be adjusted in series, and at least one filter that can be adjusted. The filter includes a filter circuit configured to be able to switch and change filter characteristics so as to reduce the influence on characteristic parts of characteristics of other filters, and filter adjustment data is supplied to each filter of this filter 1liI circuit to adjust the filter. and a control means for switching and controlling the characteristics of the at least one filter, and when performing filter adjustment of the filter circuit, the control means switches and changes the characteristics of the at least one filter. , the filter is adjusted based on a characteristic part of the characteristics of the other filter in the output characteristics of the filter circuit.

F3 effect Since the characteristics of at least one filter in the series circuit of a plurality of filters is switched and the characteristics of the other filters are clarified, filter adjustment can be performed more easily.

G, Embodiment G-1, Configuration and operation of one embodiment (FIGS. 1 and 2) FIG. 1 is a block circuit diagram showing a filter adjustment device according to one embodiment of the present invention. Analog integrated circuit 1 such as an IC for audio multiplexing and demodulation used in a television receiver
Inside, there is a filter circuit 2 to be adjusted (for example, the first
An example is shown in which a series connection circuit of two filters, ie, a filter 2A and a second filter 2B, is provided.

In FIG. 1, a filter field 2 to be adjusted is supplied with, for example, a sine wave signal from a signal source 4 via an external connection terminal (so-called IC bin) 3 of an analog integrated circuit (IC) 1. has been done. Here, the two filters 2A and 2B in the filter circuit 2 are, for example, D A variable (9), which will be described later.
The configuration is such that the circuit constants of each ζ, such as the current value of a constant current source, etc., change in accordance with the common filter adjustment data from the filter 14, and the filter characteristics change. Furthermore, at least one filter, for example 2B, can be switched in such a way as to significantly change the filter characteristics, and the frequency characteristics of filter 2B when this switch is changed are as follows:
It is set so as to reduce the influence on characteristic parts of the frequency characteristics of the other two filters, such as peaks, dips, or cutoff points. That is, as an example of the frequency characteristics of each of the two filters and 2B of this filter circuit 2, in this embodiment, ζ is a so-called trap characteristic as shown in FIG. 2A, and an LP as shown in FIG.
F (low-pass filter) characteristics are assumed, and the composite characteristics 2 of these are as shown in Figure 2 C, but the filter 2
By changing the characteristic of filter 2A as described above, the cutoff frequency of the LPF characteristic is largely moved to the high frequency side as shown by the broken line in FIG. It is made to fit completely within the overband. In the synthesized characteristic of the filter circuit 2 at the time of this switching change, the dip part of the trap characteristic of the filter 2A is clearly displayed as shown by the broken line in Fig. 2C, and the dip frequency can be easily read with high accuracy. The filter adjustment when finally adjusting this dip frequency to the predetermined frequency f0 can be easily performed at K18 degrees.

Further, in the embodiment of the present invention, the output from the filter circuit 2 is sent to level detection means, such as an AM detector 5, where the signal level (amplitude) is detected.
The detection output is sent to one input terminal, for example, a non-inverting input terminal, of a comparator 6 for level discrimination. The other input terminal (inverting input terminal) of this comparator 6 is connected to a predetermined base ? V level V ref is supplied. Comparator 6 is
This reference level V. , level discrimination is performed to determine whether the AM detection output is high or low. Further, in this embodiment, the reference level V rat is obtained from the L P l·' (low-pass filter) portion of the FM detector 7 provided in advance in the analog Icl. Of course, this FM detector 7 is supplied with the output from the filter circuit 2, and is normally connected to an LPF provided at the input stage of the FM detector, that is, an input resistor -7R and an external capacitor 7C. The DC component is taken out by the RC circuit consisting of the following, and this DC level is sent to the comparator G as the reference level V, .

The comparison output (or level discrimination output) from the comparator 6 is sent to the internal bus 10 within the IC1.

The bus decoder ll connected to the IC internal bus 10 is
It is also connected to an external bus 2o via an external connection terminal 12, and is used as an interface circuit that mutually converts data on the external bus 20 and data on the internal bus IO. External bus 20 to bus decoder 11
The data transferred to the internal bus IO via the launch circuit 13 is once stored in the launch circuit 13, then converted into an analog signal by the DA converter 14, and sent to each filter 2A, 2B in the filter circuit 2 as a filter characteristic adjustment signal. ing. The external lotus 20 includes a CPU 2 such as a so-called microprocessor.
1. ROM (ROM) in which programs, data, etc. are written in advance
Read-only memory) 22, RAM (Random Access Memory) 2 in which data etc. are temporarily written.
3, and a nonvolatile memory 24 for storing filter adjustment data, etc., which will be described later, regardless of whether the power is turned on or off. Gorera's CPU2 L ROM
22, a computer system comprising a RAM 23, a non-volatile memory 24, etc., converts the filter adjustment data in accordance with the output from the comparison means when changing the filter adjustment data as described in 1. None, a series of control operations are performed to determine optimal filter adjustment data based on this stored filter adjustment data.

G-2, Explanation of bi-odd filter (Figures 3 and 4) By the way, filters 2A and 2B incorporated inside the IC
For example, a so-called biquad filter circuit configuration as shown in FIG. 3 is often used in mm. This biquad filter is constructed by connecting in series a first integrator consisting of an operational amplifier 31 and an integrating capacitor 32, and a second integrator consisting of an operational amplifier 33 and a capacitor 34. The output of the operational amplifier 31 is supplied to the non-inverting input terminal of the operational amplifier 33.
The output of is returned to the inverting input terminal of the operational amplifier 31,
Further, the output of the operational amplifier 33 is fed back to the inverting input terminal of the operational amplifier 33 via a feedback circuit 35 with a feedback rate β. Here, B P
Characteristics such as +r, LPF, HPF, trap, or phase shifter can be realized. In the example shown in FIG. 3, by supplying an input signal to the non-inverting input terminal 36 of the operational amplifier 31, grounding the capacitor 32 and the capacitor 34, and taking out the output signal from the output terminal 37 of the operational amplifier 33, LPF is realized. This LPF
The transfer function of is s t +−βS(1.

Also, by supplying an input signal to the non-inverting input terminal of the operational amplifier 31 and the capacitor 34, grounding the capacitor 32, and taking out the output signal from the output terminal of the operational amplifier 33, s! A trap filter can be constructed with a transfer function of +1 s2+βg+1.

Next, FIG. 4 shows a specific example of one integrator used in the above-mentioned biquad filter. In this Figure 4,
The non-inverting input terminal 41 and the inverting input terminal 42 of the operational amplifier are connected to the bases of transistors 43 and 44 that constitute the differential amplifier, and are connected between the emitters of these transistors 43 and 44. A current corresponding to the input voltage between the terminals 41 and 42 flows through the resistor Rt. This current and each current r+ of a constant current source connected to each emitter of transistors 43 and 44, respectively.
, T+, the sum and difference currents of transistor 43.4
A diode 45.4 connected to each collector of 45.
The terminal voltages of the diodes 45 and 46 that flow through the transistors 46 and 46 and appear in response to these currents are respectively supplied to the bases of the transistors 47 and 48 constituting the common emitter differential (transistor pair). 47.
48 common emitters are 21. Through the constant current source 49 of °
The signal current flowing through the collector side of this pair of passive transistors is amplified by a factor of lx/I+. The collector output of transistor 48 is a current mirror circuit 1R5 consisting of diode 50a and transistor 50b.
0 and charges the capacitor 52 which becomes the integral capacitance.

The voltage at one end of this capacitor 52 is received by a transistor 54 and taken out from an output terminal 55.

The other end 53 of the capacitor 52 is supplied with input or grounded as described above.

In the integration circuit configuration of FIG. 4, the constant current source 49
By changing the current value I2 of the current source 51 on the output side of the current mirror circuit 50, a change occurs such that the characteristic curve in the frequency characteristics of the biquad filter shown in FIG. 3 moves in parallel in the frequency axis direction. In this embodiment, as will be described later, filter adjustment is performed by controlling this current value (2).

G-3. Changing filter switching (Figures 5 to 8) On the other hand, for example, changing the characteristics of filter 2B with the above-mentioned LPF (low-pass soil) characteristic requires switching the internal circuit of the filter using a switch, etc. By,
The filter characteristics are significantly changed as shown by the solid line (cutoff frequency fct) and the broken line (cutoff frequency fcz) in FIG. In order to realize this change in characteristics, in the integrator configuration shown in FIG.
ζ mutual conductance g, or the above current value 1. which corresponds to the gain of the operational amplifier. For example, switching the ratio between I2 and I2 may be carried out.

For example, FIG. 5 shows a specific example of switching the integral capacitance, and in this step 5121, the integrator in the circuit configuration of the integrator shown in FIG. For (capacitor 52),
A series circuit of switches 52, 11 and capacitor 52c2 is connected in parallel, and this switch 525. By controlling l to be on during normal times (when filter adjustment is not performed) and off during filter adjustment, the LPF characteristics are changed. That is, the capacitance value of the capacitor 52 is assumed to be C5, and the capacitor 52. When the capacitance value of t is C2, the cutoff frequency rc+ of the L P F characteristic when the switch 523w is normally in the on state is:
It becomes. On the other hand, when adjusting the filter, the switch 528w is turned off, so the cutoff frequency r
cz is switched to the LPF characteristic as shown by the broken line in FIG. 2B in (2).

Next, in the specific example of FIG. 6, a switch SW*t is connected in parallel to the emitter resistor R1 of the manual stage of the integrator.
and resistance Rt! The mutual conductance g can be switched and changed by turning off the switch sWlffi during normal operation and turning on the switch 5WIE during filter adjustment. Therefore, switch 5Wll! Cutoff frequency f during normal operation with OFF
cl becomes , and the cutoff frequency B r cm when adjusting the filter with switch SW□ turned on is ■! tRtt.

In addition, in the examples shown in FIGS. 7 and 8, the current ratio l
The gain is changed by changing x/It. First, in the example shown in FIG. 7, a constant current fi49+ of a switch 495w and a current value I is connected in parallel to the constant current source 49.
3, and in parallel to the constant current WAst, a constant current source 511.3 with a switch StS□ and a current value ■. A series circuit with each is connected. Each switch 49
, and 515w are interlocked, and are both turned off during normal times and turned on together when adjusting the filter IJl. Here, each of the constant current sources 49 and 51 usually has a current mirror IB configuration, and in this case, as shown in FIG.
Input side transistor 5 that constitutes a current mirror circuit together with each constant current fi (transistor) 49.51
A series circuit of a switch 58 and a constant current source 59 having a current value Is is connected in parallel to a constant current source 57 having a current value I2 connected to the switch 6, and this switch 58 is turned off during normal operation and turned on during adjustment. It should be configured as follows. At this time, the cutoff frequency fcI during normal operation is t [c+=□ 2πCREII, and the cutoff frequency rct when adjusting the filter with switch 5WIE turned on is 2πCRIT.

becomes.

The switching of the internal circuits of the integrators as described above may be performed for both of the two integrators constituting the biquad filter, or may be performed for only one of them.

In addition, frequency movement due to internal circuit switching is
Not limited to LPF only, various other filters,
It goes without saying that the same method can also be implemented for BPF, HPF, ) wrap filters, etc., for example.

G-4. Specific example of filter adjustment (Figures 9 and 1O) Next, the filter characteristics are switched and changed, for example, after the dip part of the trap characteristic is clarified, this dip frequency is Adjust the filter characteristics so that the target frequency f0 is achieved. Regarding this filter J high I adjustment,
For example, as in the past, the dip frequency is detected based on the filter output characteristic curve m (frequency characteristic surface MA) when the input signal frequency is changed (so-called sweep), and the soil filter is operated until the dip frequency reaches the target value f0. Although the frequency sweep described above may be repeated while adjusting the characteristics, in the embodiment of the present invention, as shown in FIG. 1, filter adjustment can be performed with high accuracy with a simple configuration, and adjustment automation may be possible. We are proposing such a system.

The outline of this filter adjustment system is to change the characteristics of the filter with respect to a human input signal fixed at a constant frequency, and to obtain the optimal filter adjustment based on the filter adjustment data when the level detection output of the filter output crosses a predetermined reference level. By obtaining filter adjustment data, it is possible to shorten filter adjustment time and improve accuracy with a simple configuration.
This allows automatic adjustment of filter characteristics.

The operation for determining the optimum filter jIil data will be explained with reference to FIGS. 1, 9, and 10.

First, the frequency characteristics of the filter circuit 2 during filter adjustment are changed by switching the characteristics of one filter 2B as described above, so that the characteristics of the other filter 2A appear almost as they are, for example, as shown by the solid line in FIG. The dip part, which is a characteristic part of the trap characteristics, as shown in Figure 2, is clearly visible. This filter circuit 2 is supplied with a constant frequency signal from the signal fX4, and at this time, CP L
A control means consisting of a combinator system such as J21 is connected to a bus decoder 11 and a tC internal bus 10.
via the latch circuit 13 and AD converter 14,
Each filter 2A in the filter circuit 2.

The filter adjustment data is sent to the control terminal of the constant current source (rO) of 2B. This adjustment data is a series of data that gradually moves the characteristic curve of the filter 2 in one direction (for example, in the direction of the arrow in the figure) on the frequency axis, as schematically shown by the broken line in FIG. This is data, and changing the filter characteristics substantially continuously in this way corresponds to changing (sweving) the frequency of the input signal in the conventional art.

On the other hand, since the input signal frequency is fixed at a constant value f0, the output obtained by level-detecting the output signal from the filter 2 with the AM detector 5 is, for example, the first θ
The detection output will look like the one shown in the figure.

In other words, the level of this detection output changes in accordance with the change in the filter adjustment data shown on the horizontal axis of FIG. 10, and is approximately like the filter characteristic curve of FIG. A curve is obtained. This detection output is sent to the non-inverting input terminal of the comparator 6 and compared with the reference level V□, thereby obtaining a comparison output (discrimination output) as shown in FIG. When the filter adjustment data at the inversion switching position of this comparison output, that is, the point at which the detected output crosses the reference level V rot, is sequentially set to D-1Db, the Q optimum when the dip frequency of the trap characteristic matches the frequency f0 is set as D-1Db. The adjustment data is the average 1 of the above adjustment data 9D, , Db
a (D-+Dh)/2 is calculated.

This is the best! The IiA adjustment data is written in the nonvolatile memory 24 shown in FIG. 1 above, and is saved even when the power is turned off. As one of the initial setting operations associated with turning on the power during normal use, the optimum adjustment data stored in the non-volatile memory 24 is sent to the launch circuit 13 via the bus 20.10 etc. Each filter 2A
, 2B, etc. are set to the optimal adjustment state.

This configuration and operation eliminates the need for the conventional frequency sweep configuration, which not only simplifies the configuration and shortens adjustment time, but also eliminates the need to monitor characteristic curves and allows the filter output to cross the reference level. With a simple configuration in which only the comparator 6 detects the filter adjustment data, optimal filter adjustment data can be obtained with high accuracy, and application to automatic adjustment using a lotus as a scissor can be easily realized.

G-5, Other Examples (Figs. 11 to 15) By the way, each filter 2A, 21 constituting the filter circuit 2
Various adjustments can be made to the adjustment of each of the filter characteristics.

For example, No. A Br'F (bandpass filter) with the frequency characteristics shown in the 11th nationality is used as the filter 2A, and an LP with the characteristics shown in the solid line in FIG. 11B is used as the second filter 2B.
When F (low-pass filter) is used, these composite characteristics become as shown by the solid line in FIG. 11C, making it difficult to confirm the peak frequency f. Therefore, in the filter 1N adjustment mode, the characteristics of the second filter 2B are changed in the same manner as in the embodiment described above, and the cutoff frequency is significantly shifted to the higher frequency side, as shown by the broken line in FIG. 11B. By moving it, the characteristics of the first filter 2A appear almost as they are as the characteristics of the filter circuit 2, as shown by Ul and I in FIG. 11C.

In addition, FIG. 12 A, B and C show the above-mentioned filters 2A and 2.
The characteristics of each filter 2A and 2B and the composite characteristic of the filter circuit 2 are shown in the case where B has a trap characteristic of a dip frequency f0 and rot, respectively.As shown by the broken line in FIG. 12B, the characteristic of filter 2B is By changing the switch and moving the dip, for example, to the higher frequency side, the dip part, which is a characteristic part of the characteristics of the filter 2A, appears as it is in the composite characteristic of the filter circuit 2 (as shown by the broken line in FIG. 12C). There is.

Furthermore, both of the two filters are BPF (Bandpass).
filter) or BPF and trap filter! ;In the case of a combination of
The curve (solid line) may be changed to a gentle curve (@cotton) to clarify the characteristic curves of other filters.Here is an example of a configuration for changing the Q value of PF. It is shown in FIG.

In FIG. 14, parts corresponding to the parts of the biquad filter shown in FIG. 3 described above are given the same reference numerals and their explanations will be omitted. The feedback circuit 35 includes resistors 35□, 3
The resistor 35R* is connected to the output terminal of the operational amplifier 33, so that the divided voltage output of the resistors 35□ and 35□ is fed back to the inverting input terminal of the operational amplifier 33. It has become. Furthermore, the above Q
As a configuration for changing the value, a resistor 35□ and a switch 355. are connected in parallel to the resistor 35111. A series circuit with is connected. This switch 35. , the feedback rate β of the feedback circuit 35 changes according to the on/off state of , and the Q value 1/β changes. That is, each resistor 35□, 35
++ and the resistance values of 35□ are R, , R1 and R, respectively.
When set to 1, Q is the Q value when the switch 35, □ is off. F and Q, which is the Q value when on. M is Q,, = -□ R3 R+//Rz R, In.

R5+)n.

becomes. In this case, since QoN>QoF, normally the switch 353w is turned on and the BP with a predetermined high Q value is set.
By realizing F and turning off the switch 355w when adjusting the filter, the Q is lowered and the curvature of the characteristic curve is increased as shown by the broken line in Figure 7+'l,'1, and the characteristic parts of the characteristics of other filters are This makes filter adjustment easier.

Next, FIG. 15 shows a DA for each filter 2A, 2B constituting the filter circuit 2 as still another embodiment of the present invention.
An example is shown in which converters 14A, 14B and latch circuits 13A, 13B are provided independently. Since the other configurations are the same as the respective parts shown in FIG. 1 described above, corresponding parts are given the same reference numerals and explanations will be omitted.

As in the example of FIG. 15, each filter 2A.

Since the filter adjustment data of 2B can be adjusted independently, when adjusting the filter, a predetermined offset is added to the filter adjustment data of one filter 2B, thereby realizing the above-mentioned switching change of filter characteristics. . Note that after the filter adjustment is completed, the obtained optimal adjustment data may be used as data for all the filters 2A and 2B, taking into account that the relative accuracy of the elements within the same IC is high.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but can be easily applied to, for example, a series connection circuit of three or more F filters. In addition, the characteristics of various filters may be significantly changed, including, for example, moving the cutoff frequency of an HPF (bypass filter) to the lower frequency side, to clarify the characteristic parts of the characteristics of other filters. I can do it. In addition, various modifications can be made without departing from the gist of the present invention.

H0 Effects of the Invention According to the filter adjustment device of the present invention, when performing filter adjustment based on the filter synthesis characteristics of the output from a series-connected circuit of a plurality of filters, at least - characteristics of the filter are compared with those of other filters. Since the switching is changed so as not to affect the characteristic peaks, dips, or cut-off point thinness of the characteristic, the characteristic parts of the other filters mentioned above clearly appear in the above composite characteristic, making it easy to adjust the filter. And it can be done with high precision.

Further, according to the embodiment of the present invention, filter 1i1 adjustment can be performed with high precision in a short time with a simple configuration, and application to automatic adjustment is also easy.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram showing a filter adjustment device according to an embodiment of the present invention, FIG. 2 is a frequency characteristic graph for explaining the operation, FIG. 3 is a block circuit diagram showing an example of a biquad filter, and FIG. The figure is a circuit diagram showing a specific example of the integrator used in the filter of FIG. 3, FIGS. 5 to 8 are circuit diagrams showing specific configuration examples for switching the filter characteristics, and FIG. and FIG. 1O is a graph for explaining a specific example of the trap filter adjustment operation.
1 to 13 are frequency characteristic graphs for explaining the main operations of other embodiments, FIG. 14 is a circuit diagram showing the main part configuration of the embodiment shown in FIG. 13, and FIG. 15 is a diagram showing other embodiments. FIG. 2 is a block circuit diagram showing an embodiment of the present invention. 2... Filter circuits 2A, 2B... Filter 10.20... Bus 13... Latch circuit 14... DA converter 21... CPU 24... Non-volatile memory

Claims (1)

[Claims] At least two filters that can be adjusted are connected in series, and at least one filter has its filter characteristics switched so as to reduce the influence on the characteristic portion of the characteristics of the other filter. a filter circuit configured to be changeable; and a control means for supplying filter adjustment data to each filter of the filter circuit to perform filter adjustment, and for controlling switching and changing characteristics of the at least one filter, When performing filter adjustment of the filter circuit, the control means switches and changes the characteristics of the at least one filter, and the filter adjustment is performed based on the characteristic part of the characteristics of the other filter in the output characteristics of the filter circuit. A filter adjustment device characterized by: