A digitally controlled analog distortion device

Abstract

The present application belongs to the technical field of musical equipment and relates to a digitally controlled analog distortion device, comprising: an input port, an output port, a control port, a plurality of filter modules, and a plurality of distortion modules; the number of the filter modules is one more than the number of the distortion modules, and the filter modules and the distortion modules are alternately connected in series to form a cascade circuit in which both the head end and the tail end are filter modules; one end of the cascade circuit is connected to the input port, and the other end of the cascade circuit is connected to the output port; the control port is connected to each filter module and each distortion module to adjust the resistance value of the digital potentiometer in the filter module and the distortion module to achieve real-time adjustment of the timbre. The present application can solve the problem of the contradiction between timbre diversity and sound quality in the prior art by using an analog circuit to simulate various classic devices to achieve timbre diversity.

Description

Technical Field

[0001] The present application relates to the technical field of music equipment, and in particular to a digitally controlled analog distortion device. Background Art

[0002] With the development of science and the advancement of technology, the requirements for the distortion effect of equipment are getting higher and higher.

[0003] In the prior art, the distortion effect of a device, taking the distortion effect of a guitar as an example, generally comes from a guitar effect pedal or a guitar amplifier head, and is mainly divided into two types: analog and digital.

[0004] Analog devices generally utilize fixed circuit designs, each with its own unique tonal characteristics. This results in natural sound, extremely low latency, and infinitely extended high-frequency harmonics, eliminating high-frequency aliasing. However, the downside is a relatively fixed tonal quality. While analog devices typically have knobs for adjusting things like treble, bass, midrange, and distortion, the tonal characteristics remain relatively fixed.

[0005] Digital audio algorithms are often used to emulate various analog devices. The advantage is that the timbre characteristics of each device can be simulated. However, the disadvantage is that the sound quality is often less than ideal due to the latency and high-frequency aliasing that is unavoidable with digital distortion.

[0006] Therefore, existing analog devices and digital devices cannot achieve the best of both worlds in terms of timbre diversity and sound quality. Summary of the Invention

[0007] Based on this, it is necessary to provide a digitally controlled analog distortion device to address the above technical problems, which can solve the problem of contradiction between timbre diversity and sound quality in the existing technology, and use an analog circuit to simulate various classic devices to achieve timbre diversity.

[0008] A digitally controlled analog distortion device comprises: an input port, an output port, a control port, a plurality of filter modules and a plurality of distortion modules;

[0009] The number of the filter modules is one more than the number of the distortion modules, and the filter modules and the distortion modules are alternately connected in series to form a cascade circuit with both the filter modules at the head end and the tail end;

[0010] One end of the cascade circuit is connected to the input port, and the other end of the cascade circuit is connected to the output port;

[0011] The control port is connected to each filter module and each distortion module to adjust the resistance of the digital potentiometer in the filter module and the distortion module to achieve real-time adjustment of the tone.

[0012] In one embodiment, the filter module is a second-order universal analog filter.

[0013] In one embodiment, the filter module includes: a first signal generator, a filter output terminal, a first amplifier, a second amplifier, a third amplifier, a first capacitor, a second capacitor, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, and a tenth resistor;

[0014] One end of the first signal generating source is connected to one end of the third resistor, and the other end of the signal generating source and one end of the first resistor are grounded;

[0015] The filter output end is respectively connected to one end of the eighth resistor, the other end of the ninth resistor, and the other end of the tenth resistor;

[0016] The first amplifier has an inverting input terminal connected to the other end of the third resistor, one end of the fourth resistor, and one end of the fifth resistor, a non-inverting input terminal connected to the other end of the first resistor and one end of the second resistor, and an output terminal connected to the other end of the fifth resistor, one end of the sixth resistor, and one end of the ninth resistor, respectively;

[0017] The second amplifier has an inverting input terminal connected to one end of the first capacitor and the other end of the sixth resistor, a non-inverting input terminal connected to ground, and an output terminal connected to the other end of the second resistor, one end of the seventh resistor, one end of the tenth resistor, and the other end of the first capacitor, respectively;

[0018] The inverting input terminal of the third amplifier is respectively connected to the other end of the seventh resistor and one end of the second capacitor, the non-inverting input terminal is grounded, and the output terminal is respectively connected to the other end of the fourth resistor, the other end of the eighth resistor and the other end of the second capacitor.

[0019] In one embodiment, for each filter module, the second resistor, the fifth resistor, the eighth resistor, the ninth resistor, and the tenth resistor are replaced by digital potentiometers, and the following conditions are satisfied:

[0020] R4=R3

[0021] C1*R6=1

[0022] C2*R7=1

[0023] In the formula, R3 is the third resistor, R4 is the fourth resistor, R6 is the sixth resistor, R7 is the seventh resistor, C1 is the first capacitor, and C2 is the second capacitor.

[0024] In one embodiment, the distortion module includes: a second signal generating source, a distortion output terminal, a power supply, a fourth amplifier, a third capacitor, a fourth capacitor, a fifth capacitor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, and two diodes;

[0025] One end of the second signal generating source is connected to one end of the third capacitor, and the other end is grounded;

[0026] One end of the power supply is grounded, and the other end is connected to the other end of the eleventh resistor and one end of the twelfth resistor;

[0027] One end of the fourth capacitor is connected to the other end of the twelfth resistor;

[0028] The inverting input terminal of the fourth amplifier is respectively connected to one end of the fifth capacitor, one end of the thirteenth resistor, the anode of a diode, the cathode of another diode, and the other end of the fourth capacitor, the non-inverting input terminal is respectively connected to the other end of the third capacitor and one end of the eleventh resistor, and the output terminal is respectively connected to the other end of the fifth capacitor, the other end of the thirteenth resistor, the cathode of a diode, the anode of another diode, and the distorted output terminal.

[0029] In one embodiment, for each distortion module, the thirteenth resistor is replaced by a digital potentiometer.

[0030] The above-mentioned digitally controlled analog distortion device uses several cascaded second-order universal analog filter circuits with adjustable parameters and several universal distortion circuits with adjustable parameters to simulate the classic universal distortion algorithm: filter->distortion->filter->distortion->filter. By replacing several resistors with digital potentiometers (the more replacements, the higher the degree of freedom and the greater the diversity of the tone), a tone control module can be used to adjust the resistance of each digital potentiometer in the analog circuit through a program, thereby adjusting each parameter of each filter. In this way, only program adjustment is required to make the audio signal have a very large tone adjustability through a purely analog path, achieve the goal of real-time intelligent adjustment of the tone, and obtain a highly free adjustable and programmable distortion circuit. This application solves the fundamental contradiction between the diversity of distortion effects and sound quality that cannot be solved in the current market. It combines the advantages of digital circuits and analog circuits, and for the first time allows pure analog circuits to be used to simulate a variety of classic devices. The specific device can be a guitar or other equipment. The user can select the device to be simulated on the screen UI. After the user selects the device, the effector MCU controls the resistance value of each digital potentiometer in the circuit through the SPI interface to achieve the desired analog circuit effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic diagram of the architecture of a digitally controlled analog distortion device according to an embodiment;

[0032] Figure 2 is a schematic diagram of a filter module in one embodiment;

[0033] Figure 3FIG. 4 is a schematic diagram of a distortion module in one embodiment. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of this application more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely for explaining this application and are not intended to limit this application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in this application without creative work are within the scope of protection of this application.

[0035] It should be noted that all directional indications in the embodiments of the present application (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0036] In addition, the terms "first," "second," and so on, used in this application are for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this application, "multiple groups" means at least two groups, such as two groups, three groups, and so on, unless otherwise specifically defined.

[0037] In this application, unless otherwise specified or limited, the terms "connect," "fix," etc. should be understood in a broad sense. For example, "fix" can mean a fixed connection, a detachable connection, or an integral connection; it can mean a mechanical connection, an electrical connection, a physical connection, or a wireless communication connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean internal communication between two elements or an interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0038] In addition, the technical solutions between the various embodiments of the present application can be combined with each other, but it must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0039] This application provides a digitally controlled analog distortion device, such as Figure 1 As shown, in one embodiment, it includes: an input port, an output port, a control port, multiple filter modules and multiple distortion modules.

[0040] The number of filter modules is one more than the number of distortion modules, and the filter modules and the distortion modules are alternately connected in series, that is, multiple filter modules and multiple distortion modules are connected in series in the form of filter module, distortion module, filter module, distortion module, and filter module to form a cascade circuit with filter modules at both the head and tail ends.

[0041] One end of the cascade circuit is connected to the input port, and the other end of the cascade circuit is connected to the output port.

[0042] The control port is connected to each filter module and each distortion module to adjust the resistance of the digital potentiometer in the filter module and the distortion module to achieve real-time adjustment of the tone.

[0043] like Figure 2 As shown, the filter module is a second-order universal analog filter, including: a first signal generating source, a filter output end, an amplifying unit, a capacitor unit and a resistor unit, the amplifying unit includes: a first amplifier, a second amplifier and a third amplifier, the capacitor unit includes: a first capacitor and a second capacitor, and the resistor unit includes: a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor and a tenth resistor.

[0044] One end of the first signal generating source is connected to one end of the third resistor, and the other end of the first signal generating source and one end of the first resistor are grounded.

[0045] The filter output end is respectively connected to one end of the eighth resistor, the other end of the ninth resistor, and the other end of the tenth resistor.

[0046] The inverting input terminal of the first amplifier is respectively connected to the other end of the third resistor, one end of the fourth resistor and one end of the fifth resistor, the non-inverting input terminal is respectively connected to the other end of the first resistor and one end of the second resistor, and the output terminal is respectively connected to the other end of the fifth resistor, one end of the sixth resistor and one end of the ninth resistor.

[0047] The inverting input terminal of the second amplifier is respectively connected to one end of the first capacitor and the other end of the sixth resistor, the non-inverting input terminal is grounded, and the output terminal is respectively connected to the other end of the second resistor, one end of the seventh resistor, one end of the tenth resistor and the other end of the first capacitor.

[0048] The inverting input terminal of the third amplifier is respectively connected to the other end of the seventh resistor and one end of the second capacitor, the non-inverting input terminal is grounded, and the output terminal is respectively connected to the other end of the fourth resistor, the other end of the eighth resistor and the other end of the second capacitor.

[0049] One end of the first capacitor is connected to the inverting input end of the second amplifier, and the other end of the first capacitor is connected to the output end of the second amplifier.

[0050] One end of the second capacitor is connected to the inverting input end of the third amplifier, and the other end of the second capacitor is connected to the output end of the third amplifier.

[0051] One end of the first resistor is grounded, and the other end is respectively connected to the non-inverting input end of the first amplifier and one end of the second resistor.

[0052] One end of the second resistor is connected to the other end of the first resistor, and the other end of the second resistor is connected to one end of the tenth resistor.

[0053] One end of the third resistor is connected to the signal generating source, and the other end is respectively connected to one end of the fourth resistor, one end of the fifth resistor and the inverting input end of the first amplifier.

[0054] One end of the fourth resistor is connected to the inverting input end of the first amplifier, and the other end is connected to the output end of the third amplifier.

[0055] One end of the fifth resistor is connected to the inverting input end of the first amplifier, and the other end is connected to the output end of the first amplifier.

[0056] One end of the sixth resistor is connected to the output end of the first amplifier, and the other end is connected to the inverting input end of the second amplifier.

[0057] One end of the seventh resistor is connected to the output end of the second amplifier, and the other end is connected to the inverting input end of the third amplifier.

[0058] One end of the eighth resistor is connected to the filter output end, and the other end is connected to the output end of the third amplifier.

[0059] One end of the ninth resistor is connected to the output end of the first amplifier, and the other end is connected to the filter output end.

[0060] One end of the tenth resistor is connected to the output end of the second amplifier, and the other end is connected to the filter output end.

[0061] right Figure 2 By analyzing the circuit, we can get the transfer function of this system as:

[0062]

[0063] in:

[0064]

[0065]

[0066] Use digital potentiometer instead of R2R5R8R9R 10 , let R4=R3, C1*R6=1, C2*R7=1, then:

[0067]

[0068] R8R9R 10 Converted to conductance:

[0069]

[0070] Therefore, b0, b1, and b2 are actually three independent normalized parameters, satisfying |b0|+|b1|+|b2|=1.

[0071] Since the denominator of the general transfer function ranges from 0 to 2, it is easy to see that as long as R5 is arranged reasonably, a2 can be freely set between 0 and 2. It is a free reduction amount. By arranging R2 reasonably according to a2, a1 can be freely set between 0 and 2.

[0072] Therefore, for each filter module, the second resistor, the fifth resistor, the eighth resistor, the ninth resistor, and the tenth resistor are replaced by digital potentiometers, and the following conditions are satisfied:

[0073] R4=R3

[0074] C1*R6=1

[0075] C2*R7=1

[0076] In the formula, R3 is the third resistor, R4 is the fourth resistor, R6 is the sixth resistor, R7 is the seventh resistor, C1 is the first capacitor, and C2 is the second capacitor.

[0077] You can get a very free and extensive filter setting, including but not limited to common low-pass, high-pass, band-stop, and band-pass filters.

[0078] The filters are cascaded using triode buffers and then fed into an adjustable distortion module.

[0079] like Figure 3 As shown, the distortion module includes: a second signal generating source, a distortion output terminal, a power supply, a fourth amplifier, a third capacitor, a fourth capacitor, a fifth capacitor, an eleventh resistor, a twelfth resistor, a thirteenth resistor and two diodes.

[0080] One end of the second signal generating source is connected to one end of the third capacitor, and the other end is grounded.

[0081] The distortion output terminal is connected to the output terminal of the fourth amplifier.

[0082] One end of the power supply is grounded, and the other end is connected to the other end of the eleventh resistor and one end of the twelfth resistor.

[0083] The inverting input terminal of the fourth amplifier is respectively connected to one end of the fifth capacitor, one end of the thirteenth resistor, the anode of a diode, the cathode of another diode, and the other end of the fourth capacitor, the non-inverting input terminal is respectively connected to the other end of the third capacitor and one end of the eleventh resistor, and the output terminal is respectively connected to the other end of the fifth capacitor, the other end of the thirteenth resistor, the cathode of a diode, the anode of another diode, and the distorted output terminal.

[0084] One end of the third capacitor is connected to the second signal generating source, and the other end is connected to the non-inverting input end of the fourth amplifier.

[0085] One end of the fourth capacitor is connected to the other end of the twelfth resistor, and the other end is connected to the inverting input end of the fourth amplifier.

[0086] One end of the fifth capacitor is connected to the inverting input end of the fourth amplifier, and the other end is connected to the output end of the fourth amplifier.

[0087] One end of the eleventh resistor is connected to the non-inverting input terminal of the fourth amplifier, and the other end is connected to the power supply.

[0088] One end of the twelfth resistor is connected to the power supply, and the other end is connected to one end of the fourth capacitor.

[0089] One end of the thirteenth resistor is connected to the inverting input terminal of the fourth amplifier, and the other end of the thirteenth resistor is connected to the output terminal of the fourth amplifier.

[0090] An anode of a diode is connected to the inverting input terminal of the fourth amplifier, and a cathode of the diode is connected to the output terminal of the fourth amplifier.

[0091] An anode of another diode is connected to the output terminal of the fourth amplifier, and a cathode of the other diode is connected to the inverting input terminal of the fourth amplifier.

[0092] For each distortion module, the thirteenth resistor is replaced by a digital potentiometer, so that the pre-gain of the distortion circuit can be freely controlled.

[0093] The above-mentioned digitally controlled analog distortion device uses several cascaded second-order universal analog filter circuits with adjustable parameters and several universal distortion circuits with adjustable parameters to simulate the classic universal distortion algorithm: filter->distortion->filter->distortion->filter. By replacing several resistors with digital potentiometers (the more replacements, the higher the degree of freedom and the greater the diversity of the tone), a tone control module can be used to adjust the resistance of each digital potentiometer in the analog circuit through a program, thereby adjusting each parameter of each filter. In this way, only program adjustment is required to make the audio signal have a very large tone adjustability through a purely analog path, achieve the goal of real-time intelligent adjustment of the tone, and obtain a highly free adjustable and programmable distortion circuit. This application solves the fundamental contradiction between the diversity of distortion effects and sound quality that cannot be solved in the current market. It combines the advantages of digital circuits and analog circuits, and for the first time allows pure analog circuits to be used to simulate a variety of classic devices. The specific device can be a guitar or other equipment. The user can select the device to be simulated on the screen UI. After the user selects the device, the effector MCU controls the resistance value of each digital potentiometer in the circuit through the SPI interface to achieve the desired analog circuit effect.

[0094] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0095] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A digitally controlled analog distortion device, characterized in that: include: An input port, an output port, a control port, a plurality of filter modules, and a plurality of distortion modules; The number of the filter modules is one more than the number of the distortion modules, and the filter modules and the distortion modules are alternately connected in series to form a cascade circuit with both the filter modules at the head end and the tail end; One end of the cascade circuit is connected to the input port, and the other end of the cascade circuit is connected to the output port; The control port is connected to each filter module and each distortion module to adjust the resistance of the digital potentiometer in the filter module and the distortion module to achieve real-time adjustment of the tone; The distortion module includes: a second signal generating source, a distortion output terminal, a power supply, a fourth amplifier, a third capacitor, a fourth capacitor, a fifth capacitor, an eleventh resistor, a twelfth resistor, a thirteenth resistor and two diodes; One end of the second signal generating source is connected to one end of the third capacitor, and the other end is grounded; One end of the power supply is grounded, and the other end is connected to the other end of the eleventh resistor and one end of the twelfth resistor; One end of the fourth capacitor is connected to the other end of the twelfth resistor; The inverting input terminal of the fourth amplifier is respectively connected to one end of the fifth capacitor, one end of the thirteenth resistor, the anode of a diode, the cathode of another diode, and the other end of the fourth capacitor, the non-inverting input terminal is respectively connected to the other end of the third capacitor and one end of the eleventh resistor, and the output terminal is respectively connected to the other end of the fifth capacitor, the other end of the thirteenth resistor, the cathode of a diode, the anode of another diode, and the distorted output terminal.

2. The digital control analog distortion device according to claim 1, characterized in that: The filter module is a second-order universal analog filter.

3. A digitally controlled analog distortion device according to claim 1 or 2, characterized in that: The filter module includes: a first signal generating source, a filter output terminal, a first amplifier, a second amplifier, a third amplifier, a first capacitor, a second capacitor, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, and a tenth resistor; One end of the first signal generating source is connected to one end of the third resistor, and the other end of the signal generating source and one end of the first resistor are grounded; The filter output end is respectively connected to one end of the eighth resistor, the other end of the ninth resistor, and the other end of the tenth resistor; The first amplifier has an inverting input terminal connected to the other end of the third resistor, one end of the fourth resistor, and one end of the fifth resistor, a non-inverting input terminal connected to the other end of the first resistor and one end of the second resistor, and an output terminal connected to the other end of the fifth resistor, one end of the sixth resistor, and one end of the ninth resistor, respectively; The second amplifier has an inverting input terminal connected to one end of the first capacitor and the other end of the sixth resistor, a non-inverting input terminal connected to ground, and an output terminal connected to the other end of the second resistor, one end of the seventh resistor, one end of the tenth resistor, and the other end of the first capacitor, respectively; The inverting input terminal of the third amplifier is respectively connected to the other end of the seventh resistor and one end of the second capacitor, the non-inverting input terminal is grounded, and the output terminal is respectively connected to the other end of the fourth resistor, the other end of the eighth resistor and the other end of the second capacitor.

4. The digital control analog distortion device according to claim 3, characterized in that: For each filter module, the second resistor, the fifth resistor, the eighth resistor, the ninth resistor, and the tenth resistor are replaced by digital potentiometers, and the following conditions are met: Where, is the third resistor, is the fourth resistor, is the sixth resistor, is the seventh resistor, is the first capacitor, is the second capacitor.

5. A digitally controlled analog distortion device according to claim 1 or 2, characterized in that: For each distortion module, the thirteenth resistor is replaced by a digital potentiometer.

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