Variable gain amplifier and dual-input amplifier

Abstract

The variable gain amplifier (4) is configured to include a divider (11) that divides a signal to be amplified into two and outputs one divided signal and the other divided signal, a first variable gain amplifier (12) that has a first variable gain characteristic in which a gain corresponding to a control signal indicating the magnitude of the envelope of the signal to be amplified is expressed by a first sigmoid function, amplifies one signal according to the first variable gain characteristic, and outputs the amplified one signal to a first amplifying element (21), and a second variable gain amplifier (13) that has a second variable gain characteristic in which a gain corresponding to the control signal is expressed by a second sigmoid function, amplifies the other signal according to the second variable gain characteristic, and outputs the amplified other signal to a second amplifying element (22). The variable gain amplifier (4) also includes a characteristic adjusting unit (14) that adjusts one or more gains of the gain of the first sigmoid function and the gain of the second sigmoid function according to the frequency of the signal to be amplified.

Description

[Technical field]

[0001] The present disclosure relates to a variable gain amplifier and a dual-input amplifier. [Background technology]

[0002] There is a variable gain amplifier device that includes a divider that divides a signal to be amplified into two and outputs one of the divided signals and the other divided signal, a first variable gain amplifier that amplifies one of the divided signals and outputs the one amplified signal to a first amplifying element, and a second variable gain amplifier that amplifies the other divided signal and outputs the other amplified signal to a second amplifying element. As such a variable gain amplifier, for example, Patent Document 1 discloses a variable gain amplifier in which a first variable gain amplifier and a second variable gain amplifier each have a variable gain characteristic in which the gain corresponding to a control signal indicating the magnitude of the envelope of the signal to be amplified is expressed by a sigmoid function in order to achieve highly efficient operation. The variable gain amplifier includes an adjustment means for adjusting the variable gain characteristic in order to broaden the bandwidth of the signal to be amplified. The adjustment of the variable gain characteristic includes adjustment of the gain width in the variable gain characteristic and adjustment of sliding the curve indicating the variable gain characteristic. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2-100406 Summary of the Invention [Problem to be solved by the invention]

[0004] The variable gain amplifier disclosed in Patent Document 1 had a problem in that even if the adjustment means adjusted the gain width or the like in the variable gain characteristic, depending on the frequency of the signal to be amplified, it may not be possible to obtain a variable gain characteristic for achieving highly efficient operation.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to obtain a variable gain amplifier device that can widen the bandwidth of the signal to be amplified more than the variable gain amplifier device disclosed in Patent Document 1. [Means for solving the problem]

[0006] A variable gain amplifier according to the present disclosure includes a divider that divides a signal to be amplified into two and outputs one divided signal and the other divided signal, a first variable gain amplifier that has a first variable gain characteristic in which a gain corresponding to a control signal indicating the magnitude of an envelope of the signal to be amplified is expressed by a first sigmoid function, amplifies one signal according to the first variable gain characteristic, and outputs the amplified one signal to a first amplifying element, and a second variable gain amplifier that has a second variable gain characteristic in which a gain corresponding to the control signal is expressed by a second sigmoid function, amplifies the other signal according to the second variable gain characteristic, and outputs the amplified other signal to a second amplifying element. The variable gain amplifier also includes a characteristic adjusting unit that adjusts one or more gains of the first sigmoid function gain and the second sigmoid function gain according to the frequency of the signal to be amplified. Effect of the Invention

[0007] According to the present disclosure, it is possible to widen the bandwidth of the signal to be amplified compared to the variable gain amplifier disclosed in Patent Document 1. [Brief description of the drawings]

[0008] [Figure 1] 1 is a configuration diagram showing a two-input amplifying device including a variable gain amplifying device 4 according to a first embodiment. [Diagram 2] FIG. 11 is an explanatory diagram showing how the gain of the first variable gain amplifier 12 changes with respect to the control signal x by adjusting the coefficient k1 of the first sigmoid function f1(x). [Diagram 3]FIG. 11 is an explanatory diagram showing how the gain of the first variable gain amplifier 12 changes with respect to the control signal x by adjusting the coefficient k2 of the first sigmoid function f1(x). [Figure 4] FIG. 11 is an explanatory diagram showing how the gain of the first variable gain amplifier 12 changes with respect to the control signal x by adjusting the coefficient k3 of the first sigmoid function f1(x). [Diagram 5] FIG. 11 is an explanatory diagram showing how the gain of the first variable gain amplifier 12 changes with respect to the control signal x by adjusting the coefficient k4 of the first sigmoid function f1(x). [Figure 6] 2 is a configuration diagram showing the inside of a first variable gain amplifier 12 of a variable gain amplifying device 4 according to the first embodiment. FIG. [Figure 7] 10 is a configuration diagram showing the inside of a first variable gain amplifier 12 of a variable gain amplifying device 4 according to a second embodiment. FIG. [Figure 8] 10 is a configuration diagram showing the inside of a first variable gain amplifier 12 of a variable gain amplifying device 4 according to a third embodiment. FIG. [Figure 9] FIG. 11 is a configuration diagram showing the inside of a first variable gain amplifier 12 of a variable gain amplifying device 4 according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] In order to describe the present disclosure in more detail, embodiments of the present disclosure will be described below with reference to the accompanying drawings.

[0010] Embodiment 1 FIG. 1 is a configuration diagram showing a two-input amplifying device including a variable gain amplifying device 4 according to a first embodiment. The dual-input amplifying device shown in FIG. The variable gain amplifying device 4 includes a distributor 11, a first variable gain amplifier 12, a second variable gain amplifier 13, and a characteristic adjusting section . The dual-input amplifier 20 includes a first amplifying element 21 and a second amplifying element 22 .

[0011] An input terminal 1 is provided with frequency information indicating the frequency of a signal to be amplified from the outside. An external signal to be amplified is applied to input terminal 2. An external control signal is applied to input terminal 3. The control signal indicates the magnitude of the envelope of the signal to be amplified that is applied to input terminal 2.

[0012] The distributor 11 distributes the signal to be amplified, which is applied to the input terminal 2, into two. Of the two signals after distribution, distributor 11 outputs one signal to first variable gain amplifier 12 and outputs the other signal to second variable gain amplifier 13.

[0013] The first variable gain amplifier 12 has a first variable gain characteristic in which the gain corresponding to the control signal is expressed by a first sigmoid function. The first variable gain amplifier 12 amplifies one of the signals output from the distributor 11 in accordance with a first variable gain characteristic, and outputs the amplified one of the signals to the first amplifying element 21 .

[0014] The second variable gain amplifier 13 amplifies the other signal output from the distributor 11 in accordance with a second variable gain characteristic, and outputs the amplified other signal to a second amplifying element. The amplitude ratio, which is the ratio between the amplitude of one signal output from distributor 11 to first variable gain amplifier 12 and the amplitude of the other signal output from distributor 11 to second variable gain amplifier 13, is also expressed by a sigmoid function.

[0015] The characteristic adjusting section 14 acquires frequency information given to the input terminal 1 . The characteristic adjustment unit 14 adjusts one or more of the gain of a first sigmoid function representing a first variable gain characteristic possessed by the first variable gain amplifier 12 and the gain of a second sigmoid function representing a second variable gain characteristic possessed by the second variable gain amplifier 13, depending on the frequency of the signal to be amplified indicated by the frequency information. The characteristic adjusting section 14 may adjust one or more of the gains of the first sigmoid function and the gains of the second sigmoid function, but may adjust each of the gains. In the variable gain amplifying device 4 shown in FIG. 1, the characteristic adjusting section 14 will be described as adjusting each gain.

[0016] The first amplifying element 21 amplifies one of the signals amplified by the first variable gain amplifier 12 . The second amplifying element 22 amplifies the other signal after the amplification by the second variable gain amplifier 13 . A composite signal of one signal amplified by the first amplifying element 21 and the other signal amplified by the second amplifying element 22 is output to an output terminal 23 .

[0017] FIG. 2 is an explanatory diagram showing how the gain of the first variable gain amplifier 12 changes with respect to the control signal x by adjusting the coefficient k1 of the first sigmoid function f1(x) shown in the following equation (1). The first sigmoid function f1(x) is a function indicating that the amplitude P1 of the signal provided to the first variable gain amplifier 12 varies with the control signal x. Adjustment of the coefficient k1 of the first sigmoid function f1(x) corresponds to adjustment of the gain width in the first variable gain characteristic. 3 is an explanatory diagram showing how the gain of the first variable gain amplifier 12 changes with respect to the control signal x by adjusting the coefficient k2 of the first sigmoid function f1(x) shown in the following equation (1). Adjustment of the coefficient k2 of the first sigmoid function f1(x) corresponds to adjustment of the gain of the first sigmoid function f1(x). 4 is an explanatory diagram showing how the gain of the first variable gain amplifier 12 changes with respect to the control signal x by adjusting the coefficient k3 of the first sigmoid function f1(x) shown in the following equation (1). The adjustment of the coefficient k3 of the first sigmoid function f1(x) corresponds to an adjustment of sliding the curve showing the first variable gain characteristic. 5 is an explanatory diagram showing how the gain of the first variable gain amplifier 12 changes with respect to the control signal x by adjusting the coefficient k4 of the first sigmoid function f1(x) shown in the following equation (1). The adjustment of the coefficient k4 of the first sigmoid function f1(x) corresponds to an adjustment of sliding the curve showing the first variable gain characteristic.

[0018] 2 to 5 show the change in gain of the first variable gain amplifier 12, but the change in gain of the second variable gain amplifier 13 is also shown as in Fig. 2 to 5. A second sigmoid function f2(x), which indicates that the amplitude P2 of the signal provided to the second variable gain amplifier 13 changes depending on the control signal x, is expressed as the following equation (2). In addition, the amplitude ratio R, which is the ratio between the amplitude P1 of the signal provided from the distributor 11 to the first variable gain amplifier 12 and the amplitude P2 of the signal provided from the distributor 11 to the second variable gain amplifier 13, is also expressed by a sigmoid function, as shown in the following equation (3).

[0019] In the formulas (1) to (4), G is the total gain of the first variable gain amplifier 12 and the second variable gain amplifier 13, P in is the amplitude of the signal to be amplified that is applied to input terminal 2.

[0020] 6 is a configuration diagram showing the inside of first variable gain amplifier 12 of variable gain amplifying device 4 according to embodiment 1. Since the inside of second variable gain amplifier 13 is similar to the inside of first variable gain amplifier 12, a configuration diagram showing the inside of second variable gain amplifier 13 is omitted. The first variable gain amplifier 12 includes a resistor 31, a power supply 32, a first control signal amplifier 33, a power supply 40, a first target signal amplifier 41, and a power supply 46. In the case of the second variable gain amplifier 13, the first control signal amplifier 33 shown in FIG. 6 is the second control signal amplifier, and the first amplified signal amplifier 41 shown in FIG. 6 is the second amplified signal amplifier.

[0021] The first control signal amplifier 33 includes a variable current source circuit 34, a transistor 35, a resistor 36, and transistors 37, 38, and 39. The first amplifier 41 for the signal to be amplified includes a resistor 42 and transistors 43 , 44 , and 45 .

[0022] One end of the resistor 31 is connected to each of the input terminal 3 and the base terminal of the transistor 37 . The other end of the resistor 31 is connected to the positive side of the power supply 32 . The positive side of the power supply 32 is connected to the other end of the resistor 31 . The negative side of the power supply 32 is connected to the ground.

[0023] The first control signal amplifier 33 amplifies the control signal based on the coefficient k2 adjusted by the characteristic adjustment section 14, and outputs the amplified control signal to the first amplifier 41 for the signal to be amplified. The variable current source circuit 34 outputs a current I ref_k2 are output to the collector terminal and the base terminal of the transistor 35, respectively.

[0024] The collector terminal of the transistor 35 is connected to the output side of the variable current source circuit 34 , the base terminal of the transistor 35 , and the base terminal of the transistor 39 . The emitter terminal of transistor 35 is connected to ground. The base terminal of the transistor 35 is connected to the output side of the variable current source circuit 34 , the collector terminal of the transistor 35 , and the base terminal of the transistor 39 .

[0025] A voltage Vcc is applied to one end of the resistor 36 . The other end of the resistor 36 is connected to the collector terminal of a transistor 37 and the base terminal of a transistor 43 .

[0026] The base terminal of the transistor 37 is connected to each of the input terminal 3 and one end of the resistor 31 . The collector terminal of the transistor 37 is connected to the other end of the resistor 36 and to the base terminal of the transistor 43 . The emitter terminal of the transistor 37 is connected to the emitter terminal of the transistor 38 and the collector terminal of the transistor 39, respectively.

[0027] The base terminal of the transistor 38 is connected to the positive side of a power supply 40 . The collector terminal of the transistor 38 is applied with a voltage Vcc. The emitter terminal of the transistor 38 is connected to the emitter terminal of the transistor 37 and the collector terminal of the transistor 39, respectively.

[0028] The base terminal of the transistor 39 is connected to the base terminal of the transistor 35 , the collector terminal of the transistor 35 , and the output side of the variable current source circuit 34 . The collector terminal of the transistor 39 is connected to the emitter terminal of the transistor 37 and the emitter terminal of the transistor 38, respectively. The emitter terminal of transistor 39 is connected to ground.

[0029] The first amplifier 41 for the signal to be amplified amplifies one of the signals output from the distributor 11 with a gain corresponding to the control signal amplified by the first amplifier 33 for the control signal, and outputs the amplified signal to the first amplification element 21.

[0030] A voltage Vcc is applied to one end of the resistor 42 . The other end of the resistor 42 is connected to the collector terminal of the transistor 43 and the output terminal V out are connected to each of the

[0031] The base terminal of the transistor 43 is connected to the other end of the resistor 36 and to the collector terminal of the transistor 37 . The collector terminal of the transistor 43 is connected to the other end of the resistor 42 and the output terminal V outare connected to each of the The emitter terminal of the transistor 43 is connected to the emitter terminal of the transistor 44 and the collector terminal of the transistor 45, respectively.

[0032] The base terminal of the transistor 44 is connected to the positive side of a power supply 46 . The collector terminal of the transistor 44 is applied with a voltage Vcc. The emitter terminal of the transistor 44 is connected to the emitter terminal of the transistor 43 and the collector terminal of the transistor 45, respectively.

[0033] The base terminal of transistor 45 is connected to the input terminal V in The input terminal V in One of the signals output from distributor 11 is provided to . The collector terminal of the transistor 45 is connected to the emitter terminal of the transistor 43 and the emitter terminal of the transistor 44, respectively. The emitter terminal of transistor 45 is connected to ground.

[0034] The positive side of the power supply 46 is connected to the base terminal of the transistor 44 . The negative side of the power supply 46 is connected to ground.

[0035] Next, the operation of the two-input amplifying device shown in FIG. 1 will be described. The distributor 11 receives a signal to be amplified that is applied to an input terminal 2 . The distributor 11 distributes the signal to be amplified into two. Of the two signals after distribution, distributor 11 outputs one signal to first variable gain amplifier 12 and outputs the other signal to second variable gain amplifier 13.

[0036] When first variable gain amplifier 12 receives one of the signals from distributor 11 , it amplifies the one of the signals in accordance with a first variable gain characteristic, and outputs the amplified one of the signals to first amplifying element 21 . When the second variable gain amplifier 13 receives the other signal from the distributor 11 , it amplifies the other signal in accordance with the second variable gain characteristic and outputs the amplified other signal to the second amplifying element 22 .

[0037] The characteristic adjusting section 14 acquires frequency information given to the input terminal 1 . The characteristic adjusting section 14 adjusts the gain of a first sigmoid function f1(x) that represents a first variable gain characteristic of the first variable gain amplifier 12, according to the frequency of the signal to be amplified that is indicated by the frequency information. Furthermore, the characteristic adjusting section 14 adjusts the gain of a second sigmoid function f2(x) representing a second variable gain characteristic of the second variable gain amplifier 13, according to the frequency of the signal to be amplified, which is indicated by the frequency information. The variable gain amplifier disclosed in Patent Document 1 includes an adjustment means for adjusting the coefficients k1, k3, and k4 of a sigmoid function that represents a variable gain characteristic. However, the adjustment means cannot adjust the coefficient k2 of the sigmoid function. Moreover, the adjustment means cannot simultaneously adjust all of the coefficients k1, k3, and k4 of the sigmoid function.

[0038] The following describes the gain adjustment of the first sigmoid function f1(x) by the characteristic adjustment unit 14. Note that the gain adjustment of the second sigmoid function f2(x) by the characteristic adjustment unit 14 is similar to the gain adjustment of the first sigmoid function f1(x), so a description thereof will be omitted. For example, the internal memory of the characteristic adjustment unit 14 stores a current I ref_k2 and the current I corresponding to the coefficient k2 of the second sigmoid function f2(x) ref_k2 The following is stored:

[0039] The current I flows from the collector terminal to the emitter terminal of transistor 39. 39 Since the transistors 35 and 39 form a current mirror, the current I ref_k2 It is determined by the current I 39is the current I flowing from the collector terminal to the emitter terminal of transistor 37 37 and the current I flowing from the collector terminal to the emitter terminal of the transistor 38. 38 Therefore, the current I 39 is expressed as the following equation (5). I 39 =I 37 +I 38 (5) The voltage difference between the base voltage of transistor 37 and the base voltage of transistor 38 is V cnt It is determined by V cnt According to the change in current I 37 and current I 38 Each of these changes. current I 37 and current I 38 Each of V cnt while the current I 39 V cnt is constant even if changes.

[0040] Next, the characteristic adjustment unit 14 adjusts the current I ref_k2 When changing the current I 37 The current I 37 The change in V cnt When the absolute value of is small, the current I changes approximately linearly. 37 The slope of the linear characteristic of the current I ref_k2 In other words, the current I 37 The slope of the linear characteristic of varies with the coefficient k2. current I 37 flows through resistor 36, creating a voltage V cnt_core is applied to the base terminal of transistor 43. V cnt When the absolute value of is small, V cnt_core is expressed as the following equation (6). Voltage V cnt_core As shown in equation (6), V cnt changes linearly with the voltage V cnt_core The slope of the current I ref_k2 It varies depending on.

[0041] TIFF0007642185000002.tif19166 In formula (6), R L is the resistance value of resistor 36, and β is the current mirror ratio between transistors 35 and 39.

[0042] The voltage difference between the base voltage of transistor 43 and the base voltage of transistor 44 is the voltage V cnt_core is determined by the voltage V cnt_core According to the change in current I 43 and current I 44 Each of these changes. Input terminal V in The signal applied to the output terminal V is distributed to the transistor 43 and the transistor 44. Since the collector terminal of the transistor 44 is short-circuited, the signal distributed to the output terminal V out Therefore, the output terminal V out The signal output from becomes the signal distributed to the transistor 43 side. Here, the signal passing through the transistor 43 is the base voltage V cnt_rf The base terminal voltage V cnt_rf is the voltage difference between the base voltage of the transistor 43 and the base voltage of the transistor 44. Therefore, the amplitude P1 (=G rf (V cnt_rf ) is expressed as the following equation (7). G rf is the gain of the first variable gain amplifier 12.

[0043] In equations (7) and (8), g1 is the mutual transconductance of transistor 45, V T is the thermal voltage, k is the Boltzmann constant, T is the absolute temperature, and q is the electron charge.

[0044] From equation (7), the base terminal voltage V cnt_rfIt can be seen that by changing the first gain variable characteristic of the first variable gain amplifier 12, it becomes a sigmoid function. Here, V cnt Base terminal voltage V cnt_rf The slope of the linear characteristic of the current I ref_k2 It varies depending on. V cnt When the absolute value of is small, the first control signal amplifier 33 cnt The amplification factor -R L ·βI ref_k2 Therefore, the amplitude P1 shown in equation (7) is expressed as the following equation (9).

[0045] TIFF0007642185000004.tif24166

[0046] Therefore, the gain of the first variable gain characteristic of the first variable gain amplifier 12 can be adjusted by the characteristic adjusting section 14 adjusting the coefficient k2 of the first sigmoid function f(x). That is, the characteristic adjustment unit 14 adjusts the control signal V cnt is applied to the input terminal 3, a current I corresponding to a coefficient k2 of the first sigmoid function f(x) is adjusted so that the gain of the first variable gain amplifier 12 corresponding to the frequency of the signal to be amplified becomes a desired gain, as shown in FIG. ref_k2 Adjust the current I ref_k2 The characteristic adjusting section 14 controls the variable current source circuit 34 to adjust the above.

[0047] When one of the signals amplified by the first variable gain amplifier 12 is provided to the first amplifying element 21, the first amplifying element 21 amplifies the one of the amplified signals. When the other signal amplified by the second variable gain amplifier 13 is provided to the second amplifying element 22, the second amplifying element 22 amplifies the other amplified signal. A composite signal of one signal amplified by the first amplifying element 21 and the other signal amplified by the second amplifying element 22 is output from an output terminal 23 .

[0048] In the above-described first embodiment, the variable gain amplifying device 4 is configured to include a divider 11 that divides a signal to be amplified into two and outputs one divided signal and the other divided signal, a first variable gain amplifier 12 that has a first variable gain characteristic in which a gain corresponding to a control signal indicating the magnitude of the envelope of the signal to be amplified is expressed by a first sigmoid function, amplifies one signal according to the first variable gain characteristic, and outputs the amplified one signal to a first amplifying element 21, and a second variable gain amplifier 13 that has a second variable gain characteristic in which a gain corresponding to the control signal is expressed by a second sigmoid function, amplifies the other signal according to the second variable gain characteristic, and outputs the amplified other signal to a second amplifying element 22. The variable gain amplifying device 4 also includes a characteristic adjusting unit 14 that adjusts one or more gains of the gain of the first sigmoid function and the gain of the second sigmoid function according to the frequency of the signal to be amplified. Therefore, the variable gain amplifier 4 can amplify a wider band of the signal to be amplified than the variable gain amplifier disclosed in Patent Document 1.

[0049] Embodiment 2 In the second embodiment, a variable gain amplifying device 4 in which characteristic adjusting section 14 adjusts coefficient k2 of the first and second sigmoid functions as well as coefficient k1 of the first and second sigmoid functions will be described.

[0050] The configuration of a two-input amplifying device including a variable gain amplifying device 4 according to embodiment 2 is similar to the configuration of a two-input amplifying device including a variable gain amplifying device 4 according to embodiment 1, and a configuration diagram showing a two-input amplifying device including a variable gain amplifying device 4 according to embodiment 2 is shown in FIG. Fig. 7 is a configuration diagram showing the inside of a first variable gain amplifier 12 of a variable gain amplifying device 4 according to embodiment 2. In Fig. 7, the same reference numerals as in Fig. 6 indicate the same or corresponding parts, and detailed explanations will be omitted. Since the inside of the second variable gain amplifier 13 is similar to the inside of the first variable gain amplifier 12, a configuration diagram showing the inside of the second variable gain amplifier 13 is omitted. The first variable gain amplifier 12 includes a resistor 31 , a power supply 32 , a first control signal amplifier 33 , a power supply 40 , a first target signal amplifier 41 , a power supply 46 , and a first gain adjustment circuit 47 . In the case of the second variable gain amplifier 13, the first gain adjustment circuit 47 shown in FIG. 7 is the second gain adjustment circuit.

[0051] The first gain adjustment circuit 47 includes a variable current source circuit 48 and a transistor 49 . The first gain adjustment circuit 47 adjusts the amplitude of the control signal amplified by the first control signal amplifier 33, based on the coefficient k1 adjusted by the characteristic adjustment unit 14. The coefficient k1 is a coefficient for adjusting the gain width in the first variable gain characteristic.

[0052] The variable current source circuit 48 outputs a current I ref_k1 are output to the collector terminal and the base terminal of the transistor 49, respectively. The collector terminal of the transistor 49 is connected to the output side of the variable current source circuit 48, the base terminal of the transistor 49, the base terminal of the transistor 45, and V in are connected to each of the The emitter terminal of transistor 49 is connected to ground. The base terminal of the transistor 49 is connected to the output side of the variable current source circuit 48, the collector terminal of the transistor 49, the base terminal of the transistor 45, and V in are connected to each of the

[0053] Next, a description will be given of the operation of the two-input amplifying device according to embodiment 2. However, since the two-input amplifying device according to embodiment 1 is similar to that according to embodiment 1 except for the characteristic adjustment unit 14 and the first gain adjustment circuit 47, the operation of the characteristic adjustment unit 14 and the first gain adjustment circuit 47 will be mainly described here. For example, the internal memory of the characteristic adjustment unit 14 stores a current I ref_k2 and the current I corresponding to the coefficient k1 of the first sigmoid function f1(x) ref_k1Each of these is stored. In addition, the internal memory of the characteristic adjustment unit 14 stores a current I ref_k2 and the current I corresponding to the coefficient k1 of the second sigmoid function f2(x) ref_k1 Each of these is stored.

[0054] The current I flows from the collector terminal to the emitter terminal of transistor 45. 45 Since the transistor 45 and the transistor 49 form a current mirror, the current I ref_k1 It is determined by the current I 45 is the current I flowing from the collector terminal to the emitter terminal of the transistor 43 43 and the current I flowing from the collector terminal to the emitter terminal of the transistor 44. 44 Therefore, the current I 45 is expressed as the following equation (10). I 45 =I 43 +I 44 (10)

[0055] The voltage difference between the base voltage of transistor 43 and the base voltage of transistor 44 is the voltage V cnt_core is determined by the voltage V cnt_core According to the change in current I 43 and current I 44 Each of these changes. current I 43 and current I 44 Each of these has a voltage V cnt_core while the current I 45 is the voltage V cnt_core is constant even if changes.

[0056] The characteristic adjustment unit 14 adjusts the current I ref_k1 When changing the current I 43 The current I 43 The change in voltage V cnt_core When the absolute value of is small, the current I changes approximately linearly. 43 The slope of the linear characteristic of the current Iref_k1 In other words, the current I 43 The slope of the linear characteristic of varies with the coefficient k1. Specifically, the characteristic adjustment unit 14 adjusts the control signal V cnt is applied to the input terminal 3, a current I corresponding to a coefficient k1 of a first sigmoid function f1(x) is calculated so that an amplitude P1 of the first variable gain amplifier 12 corresponding to the frequency of the signal to be amplified becomes a desired amplitude, as shown in FIG. ref_k1 Adjust the current I ref_k1 The characteristic adjusting section 14 controls the variable current source circuit 48 to adjust the characteristic. current I ref_k1 By performing this adjustment, the amplitude P1 shown in equation (7) is expressed as in equation (11) below.

[0057] TIFF0007642185000005.tif26166

[0058] In the above-described second embodiment, the variable gain amplifying device 4 is configured such that the first variable gain amplifier 12 further includes a first gain adjustment circuit 47 that adjusts the amplitude of the control signal amplified by the first control signal amplifier 33 based on the coefficient k1 after adjustment of the first sigmoid function by the characteristic adjustment section 14, and the second variable gain amplifier 13 further includes a second gain adjustment circuit that adjusts the amplitude of the control signal amplified by the second control signal amplifier based on the coefficient k1 after adjustment of the second sigmoid function by the characteristic adjustment section 14. Therefore, the variable gain amplifying device 4 according to the second embodiment can widen the band of the signal to be amplified compared to the variable gain amplifying device 4 according to the first embodiment.

[0059] Embodiment 3 In the third embodiment, a variable gain amplifying device 4 in which characteristic adjusting section 14 adjusts coefficients k1, k2 of the first and second sigmoid functions as well as coefficient k3 of the first and second sigmoid functions will be described.

[0060] The configuration of a two-input amplifying device including a variable gain amplifying device 4 according to embodiment 3 is similar to the configuration of a two-input amplifying device including a variable gain amplifying device 4 according to embodiment 1, or the configuration of a two-input amplifying device including a variable gain amplifying device 4 according to embodiment 2. For this reason, the configuration diagram showing a two-input amplifying device including a variable gain amplifying device 4 according to embodiment 3 is FIG.

[0061] Fig. 8 is a configuration diagram showing the inside of a first variable gain amplifier 12 of a variable gain amplifying device 4 according to embodiment 3. In Fig. 8, the same reference numerals as in Fig. 6 and Fig. 7 indicate the same or corresponding parts, and detailed explanations will be omitted. Since the inside of the second variable gain amplifier 13 is similar to the inside of the first variable gain amplifier 12, a configuration diagram showing the inside of the second variable gain amplifier 13 is omitted. The first variable gain amplifier 12 includes a resistor 31, a power supply 32, a first control signal amplifier 33, a power supply 40, a first amplifier for the signal to be amplified 41, a power supply 46, a first gain adjustment circuit 47, and a first offset addition circuit 50. In the case of the second variable gain amplifier 13, the first offset adding circuit 50 shown in FIG. 8 is the second offset adding circuit. The first variable gain amplifier 12 shown in Fig. 8 is obtained by applying the first offset adding circuit 50 to the first variable gain amplifier 12 shown in Fig. 7. However, this is merely an example, and the first offset adding circuit 50 may also be applied to the first variable gain amplifier 12 shown in Fig. 6.

[0062] The first offset adding circuit 50 includes a variable current source circuit 51 , a transistor 52 and a transistor 53 . The first offset adding circuit 50 adds an offset to the control signal amplified by the first control signal amplifier 33, based on the coefficient k3 adjusted by the characteristic adjusting section 14. The coefficient k3 is an adjustment coefficient for sliding the curve indicating the first variable gain characteristic. Specifically, the coefficient k3 is a coefficient for offsetting the first variable gain characteristic in the horizontal axis direction in FIG.

[0063] The variable current source circuit 51 outputs a current I ref_k3 to the collector terminal and the base terminal of the transistor 52, respectively. The collector terminal of the transistor 52 is connected to the output side of the variable current source circuit 51 , the base terminal of the transistor 52 , and the base terminal of the transistor 53 . The emitter terminal of transistor 52 is connected to ground. The base terminal of the transistor 52 is connected to the output side of the variable current source circuit 48 , the collector terminal of the transistor 52 , and the base terminal of the transistor 53 .

[0064] The base terminal of the transistor 53 is connected to the base terminal of the transistor 52 , the collector terminal of the transistor 52 , and the output side of the variable current source circuit 51 . The collector terminal of the transistor 53 is connected to the collector terminal of the transistor 37 , the other end of the resistor 36 , and the base terminal of the transistor 43 . The emitter terminal of the transistor 53 is connected to ground.

[0065] Next, a description will be given of the operation of the two-input amplifying device according to embodiment 3. However, since the two-input amplifying device according to embodiment 2 is similar to that according to embodiment 2 except for the characteristic adjustment unit 14 and the first offset addition circuit 50, the operation of the characteristic adjustment unit 14 and the first offset addition circuit 50 will be mainly described here. For example, the internal memory of the characteristic adjustment unit 14 stores a current I ref_k2 , the current I corresponding to the coefficient k1 of the first sigmoid function f1(x) ref_k1 and the current I corresponding to the coefficient k3 of the first sigmoid function f1(x) ref_k3 Each of these is stored. In addition, the internal memory of the characteristic adjustment unit 14 stores a current I ref_k2 , the current I corresponding to the coefficient k1 of the second sigmoid function f2(x) ref_k1and the current I corresponding to the coefficient k3 of the second sigmoid function f2(x) ref_k3 Each of these is stored.

[0066] The current I flows from the collector terminal to the emitter terminal of transistor 53. 53 Since the transistors 52 and 53 form a current mirror, the current I ref_k3 is determined by. Therefore, the characteristic adjustment unit 14 adjusts the current I ref_k3 When changing the current I 53 The current I 53 By changing the voltage V cnt_core is offset. current I 53 In response to the change in cnt_core By offsetting, the amplitude P1 shown in equation (7) is expressed as the following equation (12).

[0067] TIFF0007642185000006.tif24166In equation (12), γ is the current mirror ratio between transistor 52 and transistor 53.

[0068] The characteristic adjustment unit 14 adjusts the control signal V cnt is applied to the input terminal 3, a current I corresponding to a coefficient k3 of the first sigmoid function f(x) is calculated so that the gain of the first variable gain amplifier 12 corresponding to the frequency of the signal to be amplified becomes a desired gain, as shown in FIG. ref_k3 Adjust the current I ref_k3 The characteristic adjustment section 14 controls the variable current source circuit 51 to perform the adjustment.

[0069] In the above third embodiment, the variable gain amplifier 4 is configured such that the first variable gain amplifier 12 further includes a first offset addition circuit 50 that adds an offset to the control signal amplified by the first control signal amplifier 33 based on the coefficient k3 adjusted by the characteristic adjustment section 14, and the second variable gain amplifier 13 further includes a second offset addition circuit that adds an offset to the control signal amplified by the second control signal amplifier based on the coefficient k3 adjusted by the characteristic adjustment section 14. Therefore, the variable gain amplifier 4 according to the third embodiment can achieve a wider bandwidth for the signal to be amplified than the variable gain amplifiers 4 according to the first and second embodiments.

[0070] Embodiment 4 In the fourth embodiment, a variable gain amplifying device 4 in which characteristic adjusting section 14 adjusts coefficient k4 of the first and second sigmoid functions in addition to adjusting coefficients k1, k2, k3 of the first and second sigmoid functions will be described.

[0071] The configuration of a two-input amplifying device including a variable gain amplifying device 4 according to embodiment 4 is similar to the configuration of a two-input amplifying device including a variable gain amplifying device 4 according to embodiment 1, the configuration of a two-input amplifying device including a variable gain amplifying device 4 according to embodiment 2, or the configuration of a two-input amplifying device including a variable gain amplifying device 4 according to embodiment 3. For this reason, the configuration diagram showing a two-input amplifying device including a variable gain amplifying device 4 according to embodiment 4 is FIG.

[0072] Fig. 9 is a configuration diagram showing the inside of a first variable gain amplifier 12 of a variable gain amplifying device 4 according to embodiment 4. In Fig. 9, the same reference numerals as in Fig. 6, Fig. 7 and Fig. 8 indicate the same or corresponding parts, and therefore detailed explanations will be omitted. Since the inside of the second variable gain amplifier 13 is similar to the inside of the first variable gain amplifier 12, a configuration diagram showing the inside of the second variable gain amplifier 13 is omitted. The first variable gain amplifier 12 includes a resistor 31, a power supply 32, a first control signal amplifier 33, a power supply 40, a first amplifier 41 for the signal to be amplified, a power supply 46, a first gain adjustment circuit 47, a first offset addition circuit 50 and a third offset addition circuit 54. In the case of the second variable gain amplifier 13, the third offset adding circuit 54 shown in FIG. 9 is the fourth offset adding circuit. The first variable gain amplifier 12 shown in Fig. 9 is obtained by applying the third offset adding circuit 54 to the first variable gain amplifier 12 shown in Fig. 8. However, this is merely an example, and the third offset adding circuit 54 may also be applied to the first variable gain amplifier 12 shown in Fig. 6 or the first variable gain amplifier 12 shown in Fig. 7.

[0073] The third offset adding circuit 54 includes a variable current source circuit 55 , a transistor 56 and a transistor 57 . The third offset adding circuit 54 adds an offset to the signal amplified by the first amplifier for the signal to be amplified 41, based on the coefficient k4 adjusted by the characteristic adjusting unit 14. The coefficient k4 is an adjustment coefficient for sliding the curve indicating the first variable gain characteristic. Specifically, the coefficient k4 is a coefficient for offsetting the first variable gain characteristic in the vertical axis direction in FIG.

[0074] The variable current source circuit 55 outputs a current I ref_k4 to the collector terminal and the base terminal of the transistor 56, respectively. The collector terminal of the transistor 56 is connected to the output side of the variable current source circuit 55 , the base terminal of the transistor 56 , and the base terminal of the transistor 57 . The emitter terminal of transistor 56 is connected to ground. The base terminal of the transistor 56 is connected to the output side of the variable current source circuit 55 , the collector terminal of the transistor 56 , and the base terminal of the transistor 56 .

[0075] The base terminal of the transistor 57 is connected to the base terminal of the transistor 56 , the collector terminal of the transistor 56 , and the output side of the variable current source circuit 55 . The collector terminal of the transistor 57 is connected to the collector terminal of the transistor 43, the other end of the resistor 42, and the output terminal V out are connected to each of the The emitter terminal of the transistor 57 is connected to ground.

[0076] Next, the operation of the two-input amplifying device according to embodiment 4 will be described. However, since the two-input amplifying device according to embodiment 3 is similar to that according to embodiment 3 except for the characteristic adjustment unit 14 and the third offset addition circuit 54, the operation of the characteristic adjustment unit 14 and the third offset addition circuit 54 will be mainly described here. For example, the internal memory of the characteristic adjustment unit 14 stores a current I ref_k2 , the current I corresponding to the coefficient k1 of the first sigmoid function f1(x) ref_k1 , the current I corresponding to the coefficient k3 of the first sigmoid function f1(x) ref_k3 and the current I corresponding to the coefficient k4 of the first sigmoid function f1(x) ref_k4 Each of these is stored. In addition, the internal memory of the characteristic adjustment unit 14 stores a current I ref_k2 , the current I corresponding to the coefficient k1 of the second sigmoid function f2(x) ref_k1 , the current I corresponding to the coefficient k3 of the second sigmoid function f2(x) ref_k3 and the current I corresponding to the coefficient k4 of the second sigmoid function ref_k4 Each of these is stored.

[0077] The current I flows from the collector terminal to the emitter terminal of transistor 57. 57 Since the transistors 56 and 57 form a current mirror, the current I ref_k4 is determined by. Therefore, the characteristic adjustment unit 14 adjusts the current I ref_k4When changing the current I 57 The current I 57 The output terminal V out The voltage output from is offset. current I 57 In response to the change in cnt_core By offsetting, the amplitude P1 shown in equation (7) is expressed as in equation (13) below.

[0078] TIFF0007642185000007.tif27166In equation (13), g 11 is the gain of the third offset addition circuit 54.

[0079] The characteristic adjustment unit 14 adjusts the control signal V cnt is applied to the input terminal 3, a current I corresponding to a coefficient k4 of the first sigmoid function f(x) is calculated so that the gain of the first variable gain amplifier 12 corresponding to the frequency of the signal to be amplified becomes a desired gain, as shown in FIG. ref_k4 Adjust the current I ref_k4 The characteristic adjusting section 14 controls the variable current source circuit 55 to adjust the above.

[0080] In the above fourth embodiment, the variable gain amplifier 4 is configured so that the first variable gain amplifier 12 further includes a third offset addition circuit 54 that adds an offset to one of the signals amplified by the first amplifier for the signal to be amplified 41 based on the coefficient k4 adjusted by the characteristic adjustment section 14, and the second variable gain amplifier 13 further includes a fourth offset addition circuit that adds an offset to the other signal amplified by the second amplifier for the signal to be amplified based on the coefficient k4 adjusted by the characteristic adjustment section 14. Therefore, the variable gain amplifier 4 according to the fourth embodiment can achieve a wider band for the signal to be amplified than the variable gain amplifiers 4 according to the first to third embodiments.

[0081] In addition, the present disclosure allows free combination of the respective embodiments, modification of any of the components of each embodiment, or omission of any of the components of each embodiment. [Industrial Applicability]

[0082] The present disclosure is suitable for variable gain amplifiers and dual input amplifiers. [Explanation of symbols]

[0083] 1, 2, 3 input terminal, 4 variable gain amplifier device, 11 distributor, 12 first variable gain amplifier, 13 second variable gain amplifier, 14 characteristic adjustment section, 20 two-input amplifier, 21 first amplifying element, 22 second amplifying element, 23 output terminal, 31 resistor, 32 power supply, 33 first control signal amplifier, 34 variable current source circuit, 35 transistor, 36 resistor, 37, 38, 39 transistor, 40 power supply, 41 first amplifier for signal to be amplified, 42 resistor, 43, 44, 45 transistor, 46 power supply, 47 first gain adjustment circuit, 48 variable current source circuit, 49 transistor, 50 first offset addition circuit, 51 variable current source circuit, 52, 53 transistor, 54 third offset addition circuit, 55 variable current source circuit, 56 transistor, 57 transistor.

Claims

1. a distributor that divides a signal to be amplified into two and outputs one of the divided signals and the other divided signal; a first variable gain amplifier having a first variable gain characteristic in which a gain corresponding to a control signal indicating the magnitude of an envelope of the signal to be amplified is expressed by a first sigmoid function, amplifying the one signal in accordance with the first variable gain characteristic, and outputting the amplified one signal to a first amplifying element; a second variable gain amplifier having a second variable gain characteristic in which a gain corresponding to the control signal is expressed by a second sigmoid function, amplifying the other signal in accordance with the second variable gain characteristic, and outputting the amplified other signal to a second amplifying element; a characteristic adjustment unit that adjusts one or more gains of the first sigmoid function and the second sigmoid function in accordance with a frequency of the signal to be amplified; A variable gain amplifier comprising:

2. The characteristic adjustment unit is 2. The variable gain amplifier according to claim 1, wherein the gain of the first sigmoid function and the gain of the second sigmoid function are each adjusted in accordance with the frequency of the signal to be amplified.

3. The first sigmoid function is f １ (x), the second sigmoid function is f ２ (x), The characteristic adjustment unit is Said f １ Coefficient k of (x) ２ By adjusting the first sigmoid function f １ (x) gain is adjusted, and ２ Coefficient k of (x) ２ By adjusting the second sigmoid function f ２ 3. The variable gain amplifier according to claim 2, wherein the gain of (x) is adjusted. x is the control signal, k １ , k ２ , k ３ and k ４ are respective coefficients in the first sigmoid function and the second sigmoid function.

4. The characteristic adjustment unit is The coefficient k of the first sigmoid function is determined according to the frequency of the signal to be amplified. ２ and the coefficient k of the second sigmoid function ２ In addition to adjusting each of the coefficients k １ , coefficient k ３ and coefficient k ４ and adjusting the coefficient k １ , coefficient k ３ and coefficient k ４ 4. The variable gain amplifier according to claim 3, wherein each of the above is adjusted.

5. The first variable gain amplifier comprises: The coefficient k of the first sigmoid function after adjustment by the characteristic adjustment unit ２ a first control signal amplifier for amplifying a control signal provided from the outside based on the a first amplifier for a signal to be amplified, which amplifies one of the signals output from the distributor in accordance with the control signal amplified by the first amplifier for control signal, and outputs the amplified one of the signals to the first amplifying element; The second variable gain amplifier comprises: The coefficient k of the second sigmoid function after adjustment by the characteristic adjustment unit ２ a second control signal amplifier for amplifying a control signal provided from the outside based on the 5. The variable gain amplifier according to claim 4, further comprising a second amplifier for a signal to be amplified, which amplifies the other signal output from the distributor in accordance with the control signal amplified by the second control signal amplifier, and outputs the amplified other signal to the second amplifying element.

6. The first variable gain amplifier comprises: The coefficient k of the first sigmoid function after adjustment by the characteristic adjustment unit １ a first gain adjustment circuit that adjusts the amplitude of the control signal amplified by the first control signal amplifier based on the The second variable gain amplifier comprises: The coefficient k of the second sigmoid function after adjustment by the characteristic adjustment unit １ 6. The variable gain amplifier according to claim 5, further comprising a second gain adjustment circuit for adjusting the amplitude of the control signal amplified by said second control signal amplifier based on the above.

7. The first variable gain amplifier comprises: The coefficient k of the first sigmoid function after adjustment by the characteristic adjustment unit ３ a first offset adding circuit that adds an offset to the control signal amplified by the first control signal amplifier based on the The second variable gain amplifier comprises: The coefficient k of the second sigmoid function after adjustment by the characteristic adjustment unit ３ 6. The variable gain amplifier according to claim 5, further comprising a second offset adding circuit for adding an offset to the control signal amplified by said second control signal amplifier based on the above.

8. The first variable gain amplifier comprises: The coefficient k of the first sigmoid function after adjustment by the characteristic adjustment unit ４ a third offset adding circuit that adds an offset to one of the signals amplified by the first amplifier for the signal to be amplified based on the above-mentioned The second variable gain amplifier comprises: The coefficient k of the second sigmoid function after adjustment by the characteristic adjustment unit ４ 6. The variable gain amplifier according to claim 5, further comprising a fourth offset adding circuit for adding an offset to the other signal amplified by the second amplifier for the signal to be amplified based on the offset.

9. a distributor that divides a signal to be amplified into two and outputs one of the divided signals and the other divided signal; a first variable gain amplifier having a first variable gain characteristic in which a gain corresponding to a control signal indicating a magnitude of an envelope of the signal to be amplified is expressed by a first sigmoid function, and amplifying the one signal in accordance with the first variable gain characteristic; a second variable gain amplifier having a second variable gain characteristic in which a gain corresponding to the control signal is expressed by a second sigmoid function, and amplifying the other signal in accordance with the second variable gain characteristic; a characteristic adjustment unit that adjusts one or more gains of the first sigmoid function and the second sigmoid function in accordance with a frequency of the signal to be amplified; a dual-input amplifier having a first amplifying element for amplifying one of the signals amplified by the first variable gain amplifier and a second amplifying element for amplifying the other of the signals amplified by the second variable gain amplifier, and outputting a composite signal of the one of the signals amplified by the first amplifying element and the other of the signals amplified by the second amplifying element; A dual-input amplifier comprising:

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