A RTR frequency division method and circuit

Abstract

An RTR frequency division method and circuit, characterized by comprising a transformer, a resistor R1, and a resistor R2, wherein one of the audio signal inputs is connected to the primary coil winding of the transformer, the output end of one section of the secondary coil winding of the transformer is a positive phase high frequency audio output end, the output end of another section of the secondary coil winding of the transformer is an inverted phase high frequency audio output end, and the other audio signal input is connected to the inverted phase high frequency audio output end connected in series with the resistor R2 through the resistor R1 to become a low frequency audio output end. Compared with the prior art, the present invention has the advantages of no phase difference in the divided signal, no signal distortion when the divided signal is merged, and a simple structure.

Description

Technical Field

[0001] The invention relates to a frequency division technology, in particular to an audio signal frequency division technology. Background Art

[0002] Most of the current frequency dividers are implemented by using the LRC characteristics of capacitors, resistors, and inductors to make filter circuits. Traditional frequency divider circuits all use these two principles to achieve frequency division: capacitors pass high frequencies and block low frequencies, while inductors block high frequencies and pass low frequencies. It is very convenient to design RC or RL low-pass filters, high-pass filters, and band-pass filters using the combination of these two principles, which are particularly widely used in the audio field. These circuits have a defect, which is that they will cause phase shifts between the output signals after frequency division. For example, for a signal in parallel with a capacitor, the voltage will lag behind the current by 90 degrees, and for a signal in parallel with an inductor, the voltage will lead the current by 90 degrees. This phase shift will also vary at different frequencies, which makes the subsequent phase correction very complicated and difficult. This phase shift has a great impact on the listening experience in high-fidelity audio. In addition, traditional circuits, Since high-pass filtering and low-pass filtering belong to two channels, and it is impossible for there to be two completely identical components, the signals will be distorted when they are merged, and the waveform will highlight a certain value, so everyone has been looking for a solution; now with the development of digital technology, some engineers use DSP technology to digitize the analog signal first, then divide the frequency after mathematical processing, and then synthesize the divided analog signals separately. Although this approach achieves phase-free division, the circuit is complicated, and the signal will introduce new distortion after two conversions of A / D and D / A, which violates the principle of "simple is best" in high-fidelity audio. Summary of the invention

[0003] The object of the present invention is to provide an RTR frequency division method and circuit with simple structure, in which the divided signals have no phase difference and the divided signals are not distorted when they are combined.

[0004] The frequency division method of the present invention is implemented as follows: a signal with a frequency band range of L is introduced into the primary coil winding of a transformer with an applicable frequency band range of f0, a positive-phase signal with a frequency band range of f0 is derived from one section of the secondary coil winding of the transformer, and a reverse-phase signal with a frequency band range of f0 is derived from another section of the secondary coil winding of the transformer. After the other section of the signal with a frequency band range of L is merged with the reverse-phase signal with a frequency band range of f0, the signal with a frequency band range of f0 in the other section of the signal with a frequency band range of L is offset by the reverse-phase signal with a frequency band range of f0, and a signal with a frequency range of F0=L-f0 is derived, and the frequency band range of L is F0+f0.

[0005] The technical principle is: the signal (such as audio signal) is input from the primary coil winding of the transformer. After the input signal passes through the transformer, since the transformer itself has a frequency band response range, the signal exceeding the response range will not be able to pass through the transformer. For example, the audio transformer, the human ear's hearing range is 20Hz-20KHz, and the frequency band response range of the audio transformer can easily achieve a flat output of 200Hz-20KHz. The signal output below 200Hz will drop sharply. Therefore, when the input signal passes through such a transformer, 200Hz can be output at the output end of the secondary coil winding of the transformer. Hz or above, the central tap output terminal of the secondary coil winding of the transformer is connected to the ground, thereby the secondary coil winding is divided into two windings, which makes the output of the secondary coil winding of the transformer include a high-frequency signal derived from the positive phase end of one winding of the secondary coil winding, and an inverted high-frequency signal derived from the inverted phase end of the other winding. This inverted signal is mixed with the positive phase signal of the original input audio signal. As long as the two signals are made the same in size, such as adjusting the size of the positive phase signal of the original audio signal by an adjustable resistor or adjusting the central tap output terminal of the secondary winding, the output of the secondary coil winding of the transformer includes a high-frequency signal derived from the positive phase end of one winding of the secondary coil winding, and an inverted high-frequency signal derived from the inverted phase end of the other winding. The inverted signal is mixed with the positive phase signal of the original input audio signal. The tap position adjusts the size of the inverted signal, and the output is a signal of other frequency bands including low-frequency signals minus the high-frequency signal. Since the signal above the 20KHz frequency band is beyond the hearing range of the human ear, the low-frequency signal obtained is the hearing range of the human ear. In this frequency division method, since there are no independent inductor and capacitor elements connected in series and parallel in the electrical signal loop, only the parasitic resistance, capacitance and inductance of the components themselves, the phase shift of the signal output can be almost ignored, and the circuit structure to implement this method is simple, low cost and excellent performance.

[0006] Here, the other signal with a frequency range of L is adjusted by a variable resistor and then merged with the inverted signal with a frequency range of f0. Once the transformer structure is fixed, its input and output characteristics are not easy to change by changing the structural characteristics of the transformer. For example, it is not easy to adjust the size of the inverted signal with a frequency range of f0 by adjusting the central tap position of the secondary coil winding to obtain a signal with a frequency range of F=L-f0 minus the signal with a frequency range of f0. It is easy to adjust the size of the other signal with a frequency range of L by using a variable resistor.

[0007] Here, the above method is adopted and the applicable frequency range is selected as f n The frequency range obtained by the transformer on the previous stage is F m-1 =L-∑f n-1 The signal with a frequency range of L is divided into f0, f1, ..., f n 、F m =L-∑f nFrequency division signals with more than three different frequency ranges, n=1, 2, 3, ..., m=1, 2, 3, ..., the frequency range of L is F m + f0+∑f n .

[0008] The frequency division circuit of the present invention is implemented as follows: it includes a transformer with a frequency range of f0, a resistor R1, and a resistor R2, one of the signal input ends with a frequency range of L is connected to the primary coil winding of the transformer, the output end of one section of the secondary coil winding of the transformer is a positive-phase output end with a frequency range of f0, the output end of another section of the secondary coil winding of the transformer is an inverted-phase output end with a frequency range of f0, and the other signal input end with a frequency range of L is connected to the inverted-phase output end of the frequency range of f0 connected in series with the resistor R2 through the resistor R1 to become a signal output end with a frequency range of F0=L-f0. Since the frequency division circuit only uses two resistors and one transformer, such a frequency division circuit can be named: RTR frequency division circuit.

[0009] Here, the resistor R1 is an adjustable resistor.

[0010] The resistor R1 includes a variable resistor R11 and a resistor R12. The fixed point of the variable resistor R11 is connected in series to the signal input terminal with a frequency range of L. The moving point of the variable resistor R11 is connected in series with the resistor R12, and then connected to the output terminal with a frequency range of f0 which is inversely connected in series with the resistor R2 to become a signal output terminal with a frequency range of F0=L-f0.

[0011] The center tap output end of the secondary winding of the transformer is grounded, thereby dividing the secondary coil winding into two windings, the output end of one of the secondary coil windings is a signal output end with a positive phase frequency range of f0, and the output end of the other secondary coil winding is a signal output end with a negative phase frequency range of f0.

[0012] Alternatively, the secondary winding of the transformer consists of two groups of windings, the tail of one group of windings and the head of the other group of windings are grounded, so that the output end of one group of windings is the output end of the positive phase frequency band range f0, and the output end of the other group of windings is the output end of the negative phase frequency band range f0.

[0013] Here, the output end with the inverting frequency range f0 connected in series with the resistor R2 is connected to the first amplifier circuit, and the other path of the signal input end with the frequency range L connected to the resistor R1 is connected to the second amplifier circuit, and then connected to the output end of the first amplifier circuit. The amplifier circuit is used to prevent the inverted signal output from the output end with the inverting frequency range f0 and the signal output from the other path of the signal input end with the frequency range L from flowing back to each other.

[0014] Furthermore, a filter circuit is connected to the primary input end of the transformer. By adopting the filter circuit, the frequency division point can be adjusted through the filter circuit so as to perform frequency division according to the set frequency division point.

[0015] Compared with the prior art, the present invention has the advantages of no phase difference in the divided signals, no signal distortion when the divided signals are combined, and a simple structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention;

[0017] Figure 2 This is a schematic structural diagram of Embodiment 2 of the present invention;

[0018] Figure 3 This is a schematic diagram of the structure of Embodiment 3 of the present invention;

[0019] Figure 4 This is a schematic diagram of the structure of Embodiment 4 of the present invention;

[0020] Figure 5 This is a schematic diagram of the structure of Embodiment 5 of the present invention;

[0021] Figure 6 This is a schematic diagram of the structure of Embodiment 6 of the present invention;

[0022] Figure 7 This is a structural diagram of Example 7 of the present invention. DETAILED DESCRIPTION

[0023] The present invention is now described in further detail with reference to the accompanying drawings and embodiments:

[0024] Example 1: Figure 1 As shown, the frequency division circuit of the present invention includes a transformer T, a resistor R1, and a resistor R2. The frequency response range of the transformer is f0=200HZ-20KHZ, such as PY15000 produced by Shenzhen Pengyuan Electronic Technology Co., Ltd. One of the audio signal input ends with a frequency band range of L is connected to the primary coil winding of the transformer T, and the central tap output end of the secondary coil winding of the transformer T is grounded, thereby dividing the secondary coil winding into two sections of windings, and the output end of one section of the secondary coil winding of the transformer T is a positive phase high-frequency audio output end with a frequency band range of f0, and the output end of the other section of the secondary coil winding of the transformer T is an inverted high-frequency audio output end with a frequency band range of f0. The other way of the audio signal input end is connected to the inverted high-frequency audio output end connected in series with the resistor R2 through the resistor R1 to become a low-frequency audio output end with a frequency band range of F=L-f0, and the resistor R1 is an adjustable resistor.

[0025] Example 2: Figure 2As shown, the frequency division circuit embodiment of the present invention is based on embodiment 1, and the secondary winding of the transformer T is composed of two groups of windings, the tail of one group of windings and the head of the other group of windings are grounded, so that the output end of one group of windings is a positive phase high-frequency audio output end, and the output end of the other group of windings is a negative phase high-frequency audio output end.

[0026] Example 3: Figure 3 As shown, the frequency division circuit embodiment of the present invention is based on the embodiment 1, the resistor R1 includes a variable resistor R11 and a resistor R12, the fixed point of the variable resistor R11 is connected to the audio signal input end, the moving point of the variable resistor R11 is connected in series with the resistor R12, and then connected to the inverted high-frequency audio output end connected in series with the resistor R2 to become a low-frequency audio output end.

[0027] Example 4: Figure 4 As shown, the frequency division circuit embodiment of the present invention is based on the embodiment 1, and the inverting high-frequency audio output end connected with the resistor R2 is connected to the first amplifier circuit U1, and the other path of the audio signal input end connected with the resistor R1 is connected to the second amplifier circuit U2, and then connected to the output end of the first amplifier circuit U1.

[0028] An adjustable resistor R3 and an adjustable resistor R4 are provided, one end of which is connected to the output end of the first amplifier circuit U1 and the output end of the second amplifier circuit U2 respectively, and the other end of the adjustable resistor R3 and the adjustable resistor R4 are connected to form a low-frequency audio output end.

[0029] The adjustable resistors R3 and R4 are adjusted so that the high-frequency signal in the other channel of the audio signal has the same magnitude as the inverted high-frequency signal, thereby canceling each other out and leaving only the low-frequency signal.

[0030] Example 5: Figure 5 As shown, the frequency division circuit embodiment of the present invention is based on the embodiment 1, the transformer T adopts an audio transformer with a frequency response range of low audio frequency, and a filter circuit is connected to the input end of the primary coil winding of the transformer T. The filter circuit includes a resistor R5 and a capacitor C1. One of the audio signal input ends is connected to the primary coil winding of the transformer T through the resistor R5, and the capacitor C1 is connected in parallel to the two ends of the primary coil winding of the transformer T.

[0031] Example 6: Figure 6 As shown, the frequency division circuit embodiment of the present invention is based on embodiment 1, and a filter circuit is connected to the input end of the primary coil winding of the transformer T, the filter circuit includes a resistor R6 and a capacitor C2, one of the audio signal input ends is connected to the primary coil winding of the transformer T through the capacitor C2, and the resistor R6 is connected in parallel to the two ends of the primary coil winding of the transformer T.

[0032] The frequency division method of the present invention is implemented as follows: an audio signal including audio with a frequency band range of L is introduced into the primary coil winding of a transformer T with an applicable frequency band range of f0, a signal with a frequency band range of f0 is derived from one section of the secondary coil winding of the transformer T, and an inverted signal with a frequency band range of f0 is derived from another section of the secondary coil winding of the transformer T. After the other section of the audio signal is combined with the inverted signal with a frequency band range of f0, the signal with a frequency band range of f0 in the audio signal of the other section of the audio signal is offset by the inverted signal with a frequency band range of f0, and a signal including the audio signal with a frequency band range of F0=L-f0 is derived.

[0033] The other winding of the secondary coil winding of the transformer T derives an inverted audio signal with a frequency band range of f0, which is amplified by the first amplifier circuit U1 and then merged with the signal of the other path of the audio signal with a frequency band range of L amplified by the second amplifier circuit U2. After the signal with a frequency band range of f0 in the amplified audio signal of the other path of the audio signal with a frequency band range of L is offset by the amplified inverted signal with a frequency band range of f0, a signal including the audio signal with a frequency band range of F0=L-f0 is derived.

[0034] After the audio signal passes through the filter circuit to select the crossover point, it is introduced into the primary coil winding of the transformer T. Although the filter circuit will cause a certain phase difference between the output signal with a frequency range of f0 and the signal with a frequency range of F0=L-f0 compared to the case without the filter circuit, the audio signal can be divided at the set crossover point according to the demand. Since the phase difference generated is much smaller than that of the existing technology, it is still worthwhile to achieve the effect of arbitrary frequency division according to the crossover point relative to such a small phase difference.

[0035] like Figure 7 As shown, the above method is used and the applicable frequency range is selected as f n (f1 in the attached figure) transformer T n (T1 in the attached figure) The frequency range obtained in the previous stage is F m-1 =L-∑f n-1 The signal with a frequency range of L is divided into f0, f1, ..., f n 、F m =L-∑f n Frequency division signals with more than three different frequency ranges, n=1, 2, 3, ..., m=1, 2, 3, ..., the frequency range of L is F m + f0+∑f n , wherein the divided frequency-divided signal includes a frequency-divided signal that exceeds the audio frequency band range, and the frequency-divided signal can be a control signal with control information.

Claims

1. An RTR frequency division circuit, characterized in that: It includes a transformer with an applicable frequency range of f0, a resistor R1, and a resistor R2, one of the signal input ends with a frequency range of L is connected to the primary coil winding of the transformer, the output end of one section of the secondary coil winding of the transformer is a positive-phase output end with a frequency range of f0, and the output end of another section of the secondary coil winding of the transformer is an anti-phase output end with a frequency range of f0; The central tap output end of the secondary coil winding of the transformer T is grounded, so that the secondary coil winding is divided into two sections, the output end of one section of the secondary coil winding of the transformer T is a positive phase high frequency audio output end with a frequency band range of f0, and the output end of the other section of the secondary coil winding of the transformer T is a negative phase high frequency audio output end with a frequency band range of f0; Alternatively, the secondary winding of the transformer T consists of two groups of windings, the tail of one group of windings and the head of the other group of windings are grounded, the output end of one group of windings is a positive-phase high-frequency audio output end, and the output end of the other group of windings is a negative-phase high-frequency audio output end; The other path of the signal input end with a frequency band range of L is connected to the output end with a frequency band range of f0 which is inverted in series with a resistor R2 through a resistor R1, so that the signal with a frequency band range of f0 in the signal of the other path of the signal with a frequency band range of L and the inverted signal with a frequency band range of f0 cancel each other out, becoming a signal output end with a frequency band range of F0=L-f0.

2. The RTR frequency division circuit according to claim 1, characterized in that: Resistor R1 is an adjustable resistor.

3. The RTR frequency division circuit according to claim 2, characterized in that: The resistor R1 includes a variable resistor R11 and a resistor R12. The fixed point of the variable resistor R11 is connected to the signal input terminal with a frequency range of L. The moving point of the variable resistor R11 is connected in series with the resistor R12, and then connected to the output terminal with a frequency range of f0 which is inversely connected to the resistor R2 in series to form an output terminal with a frequency range of F0=L-f0.

4. The RTR frequency division circuit according to claim 1, characterized in that: The output end with the frequency range f0 connected in series with the inverting resistor R2 is connected to the first amplifier circuit, and the other path of the signal input end with the frequency range L connected to the resistor R1 is connected to the second amplifier circuit and then connected to the output end of the first amplifier circuit.

5. The RTR frequency division circuit according to claim 1, characterized in that: A filter circuit is connected to the primary input end of the transformer.

6. The RTR frequency division circuit according to claim 5, characterized in that: The filter circuit includes a resistor R5 and a capacitor C1. One of the signal input ends with a frequency band L is connected to the primary coil winding of the transformer through the resistor R5. The capacitor C1 is connected in parallel to both ends of the primary coil winding of the transformer.

7. The RTR frequency division circuit according to claim 5, characterized in that: The filter circuit includes a resistor R6 and a capacitor C2. One of the signal input ends with a frequency band range of L is connected to the primary coil winding of the transformer through the capacitor C2. The resistor R6 is connected in parallel to both ends of the primary coil winding of the transformer.

8. An RTR frequency division method, characterized in that: A signal with a frequency band range of L is introduced into the primary coil winding of a transformer with an applicable frequency band range of f0. A positive-phase signal with a frequency band range of f0 is derived from one section of the secondary coil winding of the transformer. A reverse-phase signal with a frequency band range of f0 is derived from another section of the secondary coil winding of the transformer. After the other section of the signal with a frequency band range of L is combined with the reverse-phase signal with a frequency band range of f0, the signal with a frequency band range of f0 in the other section of the signal with a frequency band range of L is offset by the reverse-phase signal with a frequency band range of f0, and a signal with a frequency range of F0=L-f0 is derived. The frequency range of L is F0+f0.

9. The RTR frequency division method according to claim 8, characterized in that: The other winding of the secondary coil winding of the transformer derives a signal with an inverted frequency range of f0, which is amplified and then merged with the other amplified signal of the signal with a frequency range of L. The signal with a frequency range of f0 in the amplified signal with a frequency range of L of the other amplified signal with a frequency range of L is offset by the amplified inverted signal with a frequency range of f0, and a signal with a frequency range of F0=L-f0 is derived.

10. The RTR frequency division method according to claim 8 or 9, characterized in that: Use the above method and select the applicable frequency range as f n The frequency range of the transformer obtained by the previous stage is F m-1 =L-∑f n-1 The signal with a frequency range of L is divided into f0, f1, ..., f n 、F m =L-∑f n Frequency division signals with more than three different frequency ranges, n=1, 2, 3, ..., m=1, 2, 3, ..., the frequency range of L is F m + f0+∑f n .

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