JP4437097B2 - Two-point modulation type frequency modulation device and radio transmission device - Google Patents

Description

The present invention is particularly, mobile communication terminals including mobile phones, two-point modulation type frequency modulation apparatus and a wireless transmission equipment is used in a communication device such as a base station that communicates with the mobile communication terminal Related.

  In general, a PLL (Phase Locked Loop) modulation method used for communication equipment is required to have low cost, low power consumption, good noise characteristics, and high modulation accuracy. In this PLL modulation system, in order to improve the modulation accuracy, it is desirable to make the frequency band (PLL band) of the PLL wider than the frequency band (modulation band) of the modulation signal.

  However, when the PLL bandwidth is increased, the noise characteristics are deteriorated. Therefore, a two-point modulation method has been proposed in which the PLL bandwidth is set narrower than the modulation bandwidth, and modulation within the PLL band and modulation outside the PLL band are performed at two different locations (see, for example, Patent Document 1).

  As shown in FIG. 22, the wideband modulation PLL employing the proposed two-point modulation system includes a voltage controlled oscillator (VCO) 1A, a frequency divider 1B, a phase comparator 1C, a loop filter 1D, and an adder 1E. A PLL, a modulation sensitivity table 4, a delta-sigma modulator 5, a D / A converter 6, an A / D converter 7, an adder 2, and a control unit 3 are provided.

  The PLL voltage-controlled oscillator 1A outputs an RF modulation signal. The oscillation frequency of this RF modulation signal changes according to the voltage input to the control voltage terminal Vt. The frequency divider 1B divides the frequency of the RF modulation signal output from the voltage controlled oscillator 1A. The phase comparator 1C compares the phase of the signal output from the frequency divider 1B with the phase of the reference signal, and outputs a signal corresponding to the phase difference. The loop filter 1D averages the output signal from the phase comparator 1C.

The modulation sensitivity table 4 outputs a modulation signal based on the modulation data. The D / A converter 6 converts the modulation signal output from the modulation sensitivity table 4 into an analog voltage while adjusting the gain according to the gain control signal output from the control unit 3. The delta-sigma modulator 5 performs a delta-sigma modulation on the addition signal of the modulation signal output from the modulation sensitivity table 4 and the channel selection signal output from the control unit 3 obtained by the adder 2 to divide the frequency divider. A division ratio of 1B is generated. The A / D converter 7 converts the voltage value input to the control voltage terminal Vt into a digital value, and outputs the data converted into the digital value to the control unit 3.
US Pat. No. 6,211,747

  However, in a wideband modulation PLL that employs a two-point modulation method, the input timing of the signal between the two-point modulation must match, and if the input timing difference occurs, the modulation accuracy (EVM: Error Vector Magnitude) deteriorates To do.

  In the manufacture of, for example, a mobile phone incorporating a wideband modulation PLL that employs a two-point modulation method as a communication unit, the above-described input timing difference is caused by variations in characteristics of electronic components.

  In addition, when using a mobile phone, the aforementioned input timing difference due to power fluctuation, temperature change, etc. occurs when the power is turned on. Further, in a mobile phone employing a TDMA (Time Division Multiple Access) system, the above-described input timing difference due to power fluctuation, temperature change, etc. occurs at the beginning of the time slot. These input timing differences need to be corrected in order to improve the modulation accuracy, but a specific method for how to adjust the input timing differences has not been established at present.

The present invention has been made in view of the foregoing, it is possible to reduce the input timing difference between two points modulation, two-point modulation type frequency modulation apparatus and a wireless transmission equipment capable of improving the modulation accuracy The purpose is to provide.

One aspect of the two-point modulation type frequency modulation apparatus of the present invention is set by a frequency division ratio setting unit that sets a frequency division ratio based on a first digital baseband signal and a carrier wave signal, and the frequency division ratio setting unit. Based on the frequency division ratio, the frequency divider that divides the input modulation signal is compared with the phase of the frequency division signal output from the frequency divider and the phase of the reference signal, and according to the phase difference. A phase comparator that outputs a signal, a loop filter that averages the signal output from the phase comparator, and a second digital baseband signal that has been delay-adjusted is added to the signal output from the loop filter A signal adding unit; and a voltage controlled oscillator that receives a signal output from the signal adding unit and outputs a modulation signal having an oscillation frequency corresponding to the voltage of the input signal, and is output from the voltage controlled oscillator. Modulation Is a two-point modulation type frequency modulation device comprising a PLL circuit that is input to the frequency divider, and in the timing adjustment mode for adjusting the input timing between the two-point modulation, the first digital a baseband signal, and the delay amount coefficient calculating unit a first digital baseband signal using the second digital baseband signal obtained by sign inversion, to calculate the delay amount coefficient, the amount of delay coefficients Using the delay amount coefficient calculated by the calculation unit, delay adjustment of one of the first and second digital baseband signals is performed, and the first digital baseband signal subjected to delay adjustment is divided. the ratio setting unit, or, and a delay adjusting unit for outputting the delayed adjusted second digital baseband signal to the signal addition unit, the delay amount calculating section includes a plurality A delay amount coefficient is held, and when the plurality of delay amount coefficients are sequentially supplied to the delay adjustment unit one by one, the signal amplitude output from the signal addition unit is the first and second digital basebands. By detecting the maximum value within the period of the signal amplitude by detecting in units of clock over a period corresponding to one period of the signal, the signal is obtained by sequentially performing processing for the plurality of delay amount coefficients. A configuration is adopted in which a delay amount coefficient that minimizes the maximum amplitude value is selected .

According to this configuration, since the delay amount coefficient calculation unit is provided, a change in the amplitude of the signal output from the signal addition unit included in the PLL circuit is detected, and a plurality of delay amount coefficients that are held are detected. Since the delay amount coefficient that minimizes the maximum value of the amplitude can be selected and the delay adjustment unit is provided, the first and second digital signals can be obtained using the delay amount coefficient selected by the delay amount coefficient calculation unit. The delay adjustment of one of the baseband signals is performed, and the delay-adjusted first digital baseband signal is sent to the division ratio setting unit, or the delay-adjusted second digital baseband signal is sent to the signal adding unit. Can be output. As a result, the phase shift amount of at least one of the first and second digital baseband signals can be set regardless of the frequency speed of the clock signal, and the phase shift amount is finer than the frequency speed of the clock signal. The phase difference between the first and second digital baseband signals can be reduced.

One aspect of the two-point modulation type frequency modulation apparatus of the present invention employs a configuration in which the delay amount coefficient calculating unit includes a storage table that stores information on the plurality of delay amount coefficients.

According to one aspect of the two-point modulation type frequency modulation device of the present invention, each of the plurality of delay amount coefficients held in the delay amount coefficient calculating unit is a tap coefficient, and the delay adjusting unit A digital filter that performs the delay adjustment by shifting the phase of either the first digital baseband signal or the second digital baseband signal using a tap coefficient corresponding to the delay amount coefficient selected by the amount coefficient calculation unit. The structure which is is taken.

One aspect of the two-point modulation type frequency modulation apparatus of the present invention further includes a signal inverting unit that generates the second digital baseband signal by inverting the positive and negative of the first digital baseband signal. Take.

One aspect of the two-point modulation type frequency modulation apparatus of the present invention is the signal inversion unit , the signal input unit that supplies the first digital baseband signal and the second digital baseband signal, or the delay adjustment. The configuration provided inside the part is adopted.

According to one aspect of the two-point modulation type frequency modulation apparatus of the present invention, the delay adjustment unit is configured to supply the first digital baseband signal or the second digital baseband signal to the PLL circuit. Alternatively, a configuration in which both the first digital baseband signal and the second digital baseband signal are supplied is adopted.

  The radio transmission apparatus of the present invention employs a configuration including any one of the above two-point modulation type frequency modulation apparatuses.

  According to the present invention, it is possible to provide a two-point modulation type frequency modulation device capable of reducing the input timing difference between two-point modulation and improving the modulation accuracy, and further, this two-point modulation type frequency modulation device. It is possible to provide a wireless transmission device and a wireless communication device that can form a high-quality transmission signal by mounting a modulation device.

  The essence of the present invention is to calculate a delay amount coefficient based on a change amount of an amplitude of a signal obtained by adding a digital baseband signal to an output signal output from a loop filter of a two-point modulation type PLL circuit. Accordingly, the phase difference between at least one of the digital baseband signals supplied to the two-point modulation unit is shifted to reduce the phase difference between the digital baseband signals.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
[Structure of two-point modulation type frequency modulation device]
As shown in FIG. 1, a two-point modulation type frequency modulation apparatus 10 according to Embodiment 1 of the present invention includes a voltage controlled oscillator (VCO) 110, a frequency divider 111, a phase comparator 112, and a loop filter 113. A PLL circuit 11, frequency division ratio setting means for setting a frequency division ratio of the frequency divider 111 based on the first digital baseband signal S 1 and the carrier wave signal, and a second digital baseband in the output signal of the loop filter 113. Signal adding means for adding the signal S2, delay amount coefficient calculating means for calculating a delay amount coefficient based on the amount of change in amplitude of the signal obtained by adding the second digital baseband signal S2 to the output signal of the loop filter 113, and delay The first digital baseband signal S1 and the second digital baseband signal are shifted by shifting the phase of the second digital baseband signal S2 according to the quantity coefficient. And a delay adjusting means for reducing the phase difference between the two.

  The two-point modulation type frequency modulation apparatus 10 further includes a signal input unit 12 from which a first digital baseband signal S1 and a second digital baseband signal S2 are output. In the first embodiment, “sin waves” can be practically used for the first digital baseband signal S1 and the second digital baseband signal S2 output from the signal input unit 12. In the input timing adjustment mode, the signal input unit 12 outputs a second digital baseband signal S2 that is inverted with respect to the first digital baseband signal S1 based on the timing adjustment control signal. Specifically, the signal input unit 12 outputs a “−sin wave” as the first digital baseband signal S1, and outputs a “+ sin wave” as the second digital baseband signal S2. This signal inversion control can be easily realized by providing the signal input unit 12 with, for example, an inverter circuit that inverts the first digital baseband signal S1 based on the timing adjustment control signal.

  The voltage controlled oscillator 110 of the PLL circuit 11 can change the oscillation frequency according to the voltage input to the control voltage terminal Vt. The phase comparator 112 compares the phase of the output signal output from the frequency divider 111 with the phase of the reference signal, and outputs a signal corresponding to the phase difference between the two signals. The PLL circuit 11 adds the second digital baseband signal S2 (actually, the output signal output from the filter 15 via the digital filter 18 and the digital-analog converter 14) to the output signal output from the loop filter 113. An adder 114 is further provided. The loop filter 113 averages the output signal output from the phase comparator 112.

  The frequency division ratio setting means is constructed including a frequency division ratio generation unit 13. The frequency division ratio generation unit 13 sets a frequency division ratio based on the input of the first digital baseband signal S1 and the carrier wave signal, and outputs the set frequency division ratio to the frequency divider 111. The frequency divider 111 generates a modulation signal in the PLL band based on the output signal from the frequency division ratio generation unit 13.

  The signal adding means includes a digital-analog converter 14 that converts the second digital baseband signal S2 into an analog signal, a filter 15 that removes harmonic components from the output signal output from the digital-analog converter 14, and a loop. An adder 114 that adds the output signal output from the filter 15 to the output signal output from the filter 113 is constructed.

  In this signal addition means, the output signal (second digital baseband signal S2) output from the filter 15 is added to the output signal output from the loop filter 113, thereby the PLL signal is added to the input signal of the voltage controlled oscillator 110. Out-of-band modulation can be applied.

  As shown in FIG. 1, the delay amount coefficient calculating means is constructed by including a filter coefficient calculating unit 17. In the first embodiment, a signal obtained by adding the output signal output from the filter 15 to the output signal output from the loop filter 113, that is, the output signal output from the adder 114 is used as a digital signal. Therefore, the delay amount coefficient calculating means further includes an analog-digital converter 16. The analog-to-digital converter 16 inputs the output signal output from the adder 114 of the PLL circuit 11, and therefore, between the adder 114 and the voltage controlled oscillator 110, the circuit is equivalent to the voltage control terminal Vt. Connected to the place.

  The filter coefficient calculation unit 17 includes a storage table 17M shown in FIG. The filter coefficient calculation unit 17 can calculate a delay amount coefficient corresponding to the amount of change in the amplitude of the output signal output from the adder 114, and stores the calculated delay amount coefficient as information in the storage table 17M. Has been.

  As shown in FIG. 1, the delay adjusting means is constructed with a digital filter 18 in the first embodiment. As shown in FIG. 3, the digital filter 18 includes a delay element (z conversion unit) 180, an adder 181, and multipliers 183 and 184.

  In the digital filter 18, the second digital baseband signal S 2 output from the signal input unit 12 is input to the multiplier 183 and also input to the multiplier 184 through the delay element 180. On the other hand, the delay amount coefficients (in the case of the present embodiment, tap coefficients a0 and a1) output from the filter coefficient calculation unit 17 are input to the multipliers 183 and 184, respectively.

  As shown in FIG. 2, the filter coefficient calculation unit 17 according to the present embodiment outputs tap coefficients a0 and a1 corresponding to the delay amount coefficients. Specifically, the tap coefficient a0 is output to the multiplier 183, and the tap coefficient a1 is output to the multiplier 184. The multiplier 183 multiplies the second digital baseband signal S2 by the tap coefficient a0 and outputs the result to the adder 181. The multiplier 184 multiplies the second digital baseband signal S2 that has passed through the delay element 180 by the tap coefficient a1, and outputs the result to the adder 181. The adder 181 adds the output signals output from each of the multipliers 183 and 184, and passes the output signal (second digital baseband signal S 2) subjected to delay adjustment through the digital / analog converter 14 and the filter 15. The result is output to the adder 114 of the PLL circuit 11.

[Input timing difference adjustment method of two-point modulation type frequency modulation apparatus]
Next, a method for adjusting the input timing difference between the two-point modulation in the above-described two-point modulation type frequency modulation apparatus 10 will be described.

  First, the two-point modulation type frequency modulation device 10 performs two-point modulation between the two-point modulation caused by variations in characteristics of electronic components such as the loop filter 113 and the filter 15 shown in FIG. In order to adjust the input timing, the timing adjustment mode is set.

  The timing adjustment mode is set by inputting a timing adjustment control signal to the signal input unit 12. Based on the input of the timing adjustment control signal, the signal input unit 12 outputs a first digital baseband signal (for example, -sin wave) S1 and a second digital baseband signal (for example, + sin) inverted with respect to the first digital baseband signal (for example, -sin wave) S1. Wave) S2 is output.

  The first digital baseband signal S1 is input to the frequency division ratio generator 13. The frequency division ratio generation unit 13 generates a frequency division ratio based on the first digital baseband signal S1 and the carrier wave signal, and outputs the set frequency division ratio to the frequency divider 111.

  In the PLL circuit 11, an RF modulation signal is oscillated from the voltage controlled oscillator 110, and the frequency of the oscillated RF modulation signal is divided and input to the frequency divider 111. The frequency divider 111 generates a modulation signal in the PLL band based on the output signal from the frequency division ratio generation unit 13. An output signal output from the frequency divider 111 is input to the phase comparator 112. The phase comparator 112 compares the phase of the output signal output from the frequency divider 111 with the phase of the reference signal, and outputs a signal corresponding to the phase difference between the two signals. The output signal output from the phase comparator 112 is input to the loop filter 113, and the loop filter 113 averages the output signal output from the phase comparator 112. The output signal output from the loop filter 113 is input to the adder 114.

  On the other hand, the second digital baseband signal S2 output from the signal input unit 12 is input to the digital-analog converter 14 via the digital filter 18. The digital-analog converter 14 converts the second digital baseband signal S2 from an analog signal to a digital signal, and the converted second digital baseband signal S2 is output to the filter 15. The filter 15 removes harmonic components from the output signal output from the digital-analog converter 14, and this output signal is output to the adder 114 of the PLL circuit 11. In the adder 114, the output signal output from the loop filter 113 and the output signal output from the filter 15 are added, and the added output signal is a voltage controlled oscillator according to the voltage input to the control voltage terminal Vt. 110 is output.

  Here, in the two-point modulation type frequency modulation device 10, when the input timing between the two-point modulation is coincident, as shown in FIG. 4, the output signal (−sin wave) output from the loop filter 113. When the output signal (+ sin wave) S2a output from the filter 15 is added to S1a, the amplitude of the output signal S3a output from the adder 114 has no phase difference between the output signal S1a and the output signal S2a. They cancel each other and become zero. On the other hand, if the input timings do not match, the output signal S2b output from the filter 15 is added to the output signal S1b output from the loop filter 113 as shown in FIG. In the output signal S3b output from the output device 114, an amplitude obtained by synthesizing the output signal S1b and the output signal S2b resulting from the phase difference between the output signal S1b and the output signal S2b is obtained.

  Here, as the first digital baseband signal (phase modulation data) S1 and the second digital baseband signal (phase modulation data) S2 input from the signal input unit 12, a transfer function H (s) shown in FIG. When a sine wave (+ sin wave, -sin wave) at a frequency f0 when 1 and H (s) intersect is selected, when the timing of two-point modulation matches, as shown in FIG. The value of S3 can be zero. However, it is difficult to select the frequency f0 due to variations in the loop filter 113 and the like. In practice, a sine wave having a frequency different from the frequency f0 is input, such as the frequency f1 shown in FIG. become. Therefore, a difference occurs in the gain for each modulation input, so that the amplitude of the output signal S3 is zero even when the timings of the first digital baseband signal S1 and the second digital baseband signal S2 match. Don't be. Furthermore, as described above, the amplitude of the output signal S3 increases as the timing of the first digital baseband signal S1 and the second digital baseband signal S2 shifts. Therefore, the delay amount coefficient calculating means performs delay adjustment by obtaining a delay amount coefficient that minimizes the amplitude of the output signal S3.

  In the delay amount coefficient calculating means, the delay amount coefficient is calculated by the following procedure based on the amplitude change amount of the output signal S3 output from the adder 114 of the PLL circuit 11.

  First, it is assumed that the input timings between the two-point modulations coincide with each other, and the tap coefficient a0 “8/8” corresponding to the delay amount coefficient “0” stored in the storage table 17M shown in FIG. , A1 “0/8” is output from the filter coefficient calculation unit 17. At this time, the digital filter 18 outputs a second digital baseband signal S2 that is not substantially subjected to delay adjustment.

  Here, as shown in FIG. 7, the delay amount coefficient stored in the storage table 17M of the filter coefficient calculation unit 17 shown in FIG. 2 equally divides one clock signal (from the rising edge to the next rising edge) into eight parts, “0”, “1”, “2”,..., “8”. The Ts ratio represents the ratio of the delay interval to one clock signal. That is, the first delay amount coefficient “0” has a Ts ratio “0/8” and is a coefficient that does not effectively adjust the delay of the second digital baseband signal S2. The delay amount coefficient “1” has a Ts ratio of “1/8”, and is a coefficient for delay adjustment by shifting the phase of the second digital baseband signal S2 by 1/8 of one clock signal. The delay amount coefficient “2” is a Ts ratio “2/8”, and is a coefficient for delay adjustment by shifting the phase of the second digital baseband signal S2 by 2/8 of one clock signal. Hereinafter, similarly, the last delay amount coefficient “8” is the Ts ratio “8/8”, and the phase shift of the second digital baseband signal S2 is 8/8 of one clock signal, that is, one clock signal. Is a coefficient for delay adjustment.

  In the first embodiment, one clock signal is divided into eight for ease of understanding, but basically, it is preferably a multiple of two, and thus one clock is divided in this way. Thus, the accuracy can be improved while improving the sensitivity.

  The second digital baseband signal S2 output from the digital filter 18 and substantially not subjected to delay adjustment is output to the filter 15 through the digital-analog converter 14, and is output from the filter 15 as shown in FIG. Signal S2b is output. The output signal S2b is added to the output signal S1b output from the loop filter 113 in the adder 114, and the adder 114 outputs the output signal S3b shown in FIG.

In the analog-to-digital converter 16, analog data (a, b, c, d,...) Of the output signal (sin wave) S3b for one cycle output from the adder 114 is generated for each clock signal (for example, the rising edge of the clock signal). Every time). The converted digital data is taken into the filter coefficient calculation unit 17. The filter coefficient calculation unit 17 obtains the maximum value and the minimum value of the compared digital data while comparing the acquired digital data with the digital data acquired before one clock signal, and finally outputs the output signal. The maximum value W ₀ of the amplitude of S3b is calculated.

When the filter coefficient calculation unit 17 calculates the maximum amplitude value W ₀ (when it is detected that the input timing does not match), the delay amount coefficient “0” stored in the storage table 17M is used. The change is made to “1”. With the change to the delay amount coefficient “1”, the filter coefficient calculation unit 17 taps a0 “7/8” and a1 “1/8” corresponding to the delay amount coefficient “1” as shown in FIG. Is output. At this time, the digital filter 18 shifts the phase of the second digital baseband signal S2 by 1/8 of one clock signal shown in FIG. As shown in FIG. 8, the value of the amplitude direction of the second digital baseband signal S2 can be changed by changing the tap coefficients a0 and a1. As a result, the phase is shifted, and the digital filter 18 has one clock. The second digital baseband signal S2c delayed by 1/8 of the signal can be output.

The second digital baseband signal S2c generated in the digital filter 18 is input to the filter 15 via the digital-analog converter 14. The output signal output from the filter 15 and the output signal output from the loop filter 113 are output to the adder 114. The adder 114 calculates the maximum amplitude value W ₁ as shown in FIG. 6 from the output signal obtained by adding both output signals in the same manner as described above.

The filter coefficient calculation unit 17 compares the maximum amplitude W ₀ of the output signal calculated earlier with the maximum amplitude W ₁ of the output signal calculated later. Then, as shown in FIG. 9, by repeating these series of procedures until the amplitude of the output signal S3c becomes the minimum value W _min, obtaining the delay amount coefficient amplitude of the output signal S3c becomes the minimum value W _min be able to. The obtained delay amount coefficients (tap coefficients a0, a1) are held in the digital filter 18 and used to adjust the input timing difference between the two-point modulation.

  Thus, the optimum tap coefficients a0 and a1 that minimize the input timing difference between the two-point modulation are detected and held. During actual two-point modulation processing (in normal mode), the baseband signal to be transmitted is input from the signal input unit 12 to both the frequency division ratio generation unit 13 and the digital filter 18.

  The frequency characteristics of the digital filter 18 are shown in FIG. In FIG. 10, the horizontal axis represents the sampling frequency [fs], and the vertical axis represents the gain [dB]. The frequency characteristic D is a frequency characteristic of the digital filter 18 set to the delay amount coefficient “4”, that is, the tap coefficient a0 “4/8” and the tap coefficient a1 “4/8”. The frequency characteristic E is the frequency characteristic of the digital filter 18 set to the delay amount coefficient “5”, that is, the tap coefficient a0 “3/8” and the tap coefficient a1 “5/8”. In the case of the present embodiment, the digital filter 18 used for delay adjustment of the second digital baseband signal S2 targets a frequency that is sufficiently lower than the sampling frequency. In FIG. 10, since the flat characteristic is shown in the low sampling frequency region indicated by hatching, the absolute amplitude of the second digital baseband signal S2 passing through the digital filter 18 is not shifted.

[System configuration of wireless transmitter]
FIG. 11 shows a configuration in which the two-point modulation type frequency modulation apparatus 10 of the present embodiment is mounted on a radio transmission apparatus that employs a polar modulation transmission method. As shown in FIG. 11, the radio transmission apparatus 20 includes an amplitude phase separation unit 21, an amplitude modulation signal amplifier 22, the above-described two-point modulation type frequency modulation apparatus (frequency synthesizer) 10, a high frequency power amplifier 24, an antenna, 25. A baseband modulation signal composed of an I (in-phase) component and a Q (quadrature) component is input to the amplitude / phase separation unit 21. The amplitude phase separation unit 21 outputs the amplitude component of the baseband modulation signal (that is, √ (I ² + Q ² )) as an amplitude modulation signal to the amplitude modulation signal amplifier 22 and also the phase component of the baseband modulation signal ( For example, the angle formed by the modulation symbol and the I axis is output to the two-point modulation type frequency modulation apparatus 10 as a baseband phase modulation signal.

  The two-point modulation type frequency modulation device 10 generates an RF modulation signal (high frequency phase modulation signal) by modulating a carrier wave signal (carrier frequency data) with a baseband phase modulation signal (first digital baseband signal S1). This is output to the high frequency power amplifier 24. Specifically, as described above, in the state where the optimum tap coefficients a0 and a1 that minimize the input timing difference between the two-point modulation are held in the digital filter 18, the frequency division ratio generator 13 and the digital filter 18 are retained. The digital baseband signal S1 to be transmitted is input to the two-point modulation type frequency modulation.

  The high frequency power amplifier 24 is composed of a nonlinear amplifier, and the power supply voltage value of the high frequency power amplifier 24 is set according to the amplitude modulation signal amplified by the amplitude modulation signal amplifier 22. As a result, a signal obtained by multiplying the power supply voltage value by the RF modulation signal output from the two-point modulation type frequency modulation device 10 is amplified by the gain of the high-frequency power amplifier 24 and output from the high-frequency power amplifier 24 as a transmission signal. The transmission signal is transmitted from the antenna 25.

  Thus, in the radio transmission apparatus 20 that employs the polar modulation transmission method, the RF modulation signal input to the high-frequency power amplifier 24 can be a constant envelope signal that does not have a fluctuation component in the amplitude direction. A high-efficiency nonlinear amplifier can be used as the high-frequency power amplifier 24.

  As described above, according to the two-point modulation type frequency modulation apparatus 10 according to the first embodiment, a signal obtained by adding the output signal output from the filter 15 to the output signal output from the loop filter 113 (adder 114). The first digital baseband signal is detected by shifting the phase of the second digital baseband signal S2 in accordance with the amplitude change amount (adjusting the delay). The phase difference between S1 and the second digital baseband signal S2 can be reduced. Therefore, in the two-point modulation type frequency modulation device 10, the input timing difference between the two-point modulation can be reduced, and the modulation accuracy can be improved.

  Furthermore, according to the two-point modulation type frequency modulation apparatus 10 according to the first embodiment, the amount of change in the amplitude of the signal obtained by adding the output signal output from the filter 15 to the output signal output from the loop filter 113 is detected. Since the tap coefficient of the digital filter 18 is adjusted according to the amount of change in amplitude and the phase of the second digital baseband signal S2 is shifted, the phase shift amount is set regardless of the frequency speed of the clock signal. The phase of the second digital baseband signal S2 can be shifted by a phase shift amount smaller than the frequency speed of the clock signal, and the first digital baseband signal S1 and the second digital baseband can be shifted. The phase difference with the signal S2 can be reduced. Therefore, in the two-point modulation type frequency modulation device 10, the input timing difference between the two-point modulation can be further reduced, and the modulation accuracy can be further improved.

(Embodiment 2)
The second embodiment of the present invention describes an example in which the digital baseband signal inversion method is changed in the input timing adjustment mode between two-point modulations in the two-point modulation type frequency converter 10 according to the first embodiment. It is.

  As shown in FIG. 12, the two-point modulation type frequency modulation apparatus 10 according to the second embodiment includes a signal input unit 12 that outputs the first digital baseband signal S1 to the frequency division ratio generation unit 13 and the digital filter 18. A digital filter that generates a second digital baseband signal S2 obtained by inverting the first digital baseband signal S1 in the input timing adjustment mode, and outputs the second digital baseband signal S2 by delay adjustment by phase shift. 18 (delay adjustment means).

  As shown in FIG. 13, the digital filter 18 has the same basic configuration as that of the digital filter 18 of the two-point modulation type frequency converter 10 according to the first embodiment, but further includes a timing adjustment mode switching unit 185 and a multiplier. Vessels 186 and 187. The timing adjustment mode switching unit 185 is basically composed of a selector. The timing adjustment mode switching unit 185 multiplies the timing adjustment control signal for switching the timing adjustment mode and the output signal corresponding to each of the tap coefficients a0 and a1 in the timing adjustment mode, and the first digital baseband signal S1. Are inverted control signals “+1” and “−1”, which generate a second digital baseband signal S2 in which is inverted. In the normal mode, the timing adjustment mode switching unit 185 outputs the output signal “1” to the multipliers 186 and 187.

  Thus, according to the two-point modulation type frequency conversion device 10 and the two-point modulation type frequency modulation method according to the second embodiment, the digital filter 18 can be used even if the signal input unit 12 does not have a digital baseband signal inversion function. In addition, an inverted signal of the digital baseband signal can be generated with a simple configuration including the timing adjustment mode switching unit 185 and the multipliers 186 and 187.

(Embodiment 3)
The third embodiment of the present invention describes an example in which the digital baseband signal is not inverted in the input timing adjustment mode in the two-point modulation type frequency modulation apparatus 10 according to the second embodiment.

  As shown in FIG. 14, the two-point modulation type frequency modulation apparatus 10 according to the third embodiment is basically a signal having the same structure as the signal input unit 12 of the two-point modulation type frequency modulation apparatus 10 according to the second embodiment. The input unit 12 includes a digital filter 18 having basically the same structure as the digital filter 18 of the two-point modulation type frequency modulation apparatus 10 according to the first embodiment. In the case of the present embodiment, the signal input unit 12 outputs the first digital baseband signal S1 to the frequency division ratio generation unit 13 and the digital filter 18. The digital filter 18 generates and outputs a second digital baseband signal S2 that is the same as the first digital baseband signal S1 and is not inverted in the input timing adjustment mode and the normal mode.

  Here, in the two-point modulation type frequency modulation device 10, when the input timing between the two-point modulation is coincident, as shown in FIG. 15, the output signal (+ sin wave) S1a output from the loop filter 113 is obtained. When the output signal (+ sin wave) S2a output from the filter 15 is added to the output signal S3a, the output signal S3a output from the adder 114 has no phase difference between the output signal S1a and the output signal S2a. A signal having the maximum amplitude is obtained by adding the signals S1a and S2a. That is, the amplitude of the output signal S3a is opposite to the amplitude of the output signal S3a shown in FIG. 4 according to the first embodiment. On the other hand, if the input timings do not match, the output signal S2b output from the filter 15 is added to the output signal S1b output from the loop filter 113 as shown in FIG. In the output signal S3b output from the output device 114, the amplitude decreases due to the phase difference between the output signal S1b and the output signal S2b.

  Based on the amount of change in the amplitude of the output signal S3 output from the adder 114 of the PLL circuit 11, the delay amount coefficient calculation means (filter coefficient calculation unit 17) is similar to the procedure according to the first embodiment. A delay amount coefficient (tap coefficient) can be calculated using a procedure, and based on this delay amount coefficient (tap coefficient), delay control of the second digital baseband signal S2 is performed by the delay adjusting means (digital filter 18). Can be done.

  Therefore, according to the two-point modulation type frequency modulation device 10 of the present embodiment, the input timing difference between the two-point modulation can be reduced, and the modulation accuracy can be improved. Further, in the two-point modulation type frequency modulation device 10, since it is not necessary to invert the second digital baseband signal S2 with respect to the first digital baseband signal S1, the circuit configuration for generating this inverted signal is reduced. can do.

(Embodiment 4)
The fourth embodiment of the present invention is an example in which the digital filter 18 of the two-point modulation type frequency modulation apparatus 10 according to the second embodiment shown in FIG. 12 is inserted between the signal input unit 12 and the division ratio generation unit 13. Is described. That is, as shown in FIG. 17, the two-point modulation type frequency modulation apparatus 10 according to the fourth embodiment receives the first digital baseband signal S1 output from the signal input unit 12, and the first digital baseband signal S1. A digital filter 18 that outputs the digital baseband signal S1 to the frequency division ratio generation unit 13 is provided. In each of the two-point modulation type frequency modulation apparatuses 10 according to the first to third embodiments, the digital filter 18 is disposed in the supply path of the second digital baseband signal S2. In the two-point modulation type frequency modulation device 10 according to the fourth embodiment, the digital filter 18 is disposed in the supply path of the first digital baseband signal S1.

  As described above, according to the two-point modulation type frequency modulation apparatus 10 and the two-point modulation type frequency modulation method according to the fourth embodiment, the delay control of the first digital baseband signal S1 is performed in the input timing adjustment mode. Thus, the optimum tap coefficient that minimizes the input timing difference between the two-point modulation is detected and held. During actual two-point modulation processing (in normal mode), the digital baseband signal input to the frequency division ratio generation unit 13 is delay-adjusted by the digital filter 18 using the optimal tap coefficient, The input timing difference between the two-point modulation is reduced and the modulation accuracy is improved.

(Embodiment 5)
The fifth embodiment of the present invention combines the two-point modulation type frequency modulation device 10 according to the second embodiment shown in FIG. 12 and the two-point modulation type frequency modulation device 10 according to the fourth embodiment shown in FIG. An example will be described. That is, the two-point modulation type frequency modulation apparatus 10 according to the fifth embodiment includes a first digital filter 18A inserted between the signal input unit 12 and the division ratio generation unit 13, as shown in FIG. The second digital filter 18B inserted between the signal input unit 12 and the digital-analog converter 14 is provided. The first digital filter 18A is disposed in the supply path of the first digital baseband signal S1, and performs delay control of the first digital baseband signal S1. The second digital filter 18B is disposed in the supply path of the second digital baseband signal S2, and performs delay control of the second digital baseband signal S2.

  Thus, according to the two-point modulation type frequency modulation apparatus 10 and the two-point modulation type frequency modulation method according to the fifth embodiment, in the input timing adjustment mode, the first digital baseband signal S1 and the second digital base By performing the delay control of the band signal S2, the optimum tap coefficient that minimizes the input timing difference between the two-point modulation is detected and held. During actual two-point modulation processing (in normal mode), the digital baseband signal input to the frequency division ratio generation unit 13 is delay-adjusted by the first digital filter 18A using the optimal tap coefficient. The baseband signal input to the D / A converter 14 is delay-adjusted using the optimal tap coefficient by the second digital filter 18B, thereby reducing the input timing difference between the two-point modulations and modulating accuracy. To improve.

(Embodiment 6)
In FIG. 11 of Embodiment 1 described above, the example in which the two-point modulation type frequency modulation apparatus 10 of the present invention is mounted on a radio transmission apparatus adopting a polar modulation transmission system has been described. The apparatus is not limited to a wireless transmission apparatus adopting a polar modulation transmission method, but can be applied to various other wireless transmission apparatuses and various wireless communication apparatuses having a reception function.

  FIG. 20 shows a configuration example of a wireless transmission device provided with the two-point modulation type frequency modulation device 10 of the present invention. The wireless transmission device 30 includes the above-described two-point modulation type frequency modulation device (frequency synthesizer) 10, an amplifier 31, and an antenna 25. As described above, the two-point modulation type frequency modulation device 10 detects and holds the optimum tap coefficient that minimizes the input timing difference between the two-point modulation, and then holds the optimum tap coefficient by a digital filter in the normal transmission mode. An RF modulation signal (high-frequency phase modulation signal) is generated by modulating the carrier signal (carrier frequency data) with the baseband signal while delay-adjusting the baseband signal using an appropriate tap coefficient. Output. The transmission signal amplified by the amplifier 31 is transmitted from the antenna 25. Thereby, in the wireless transmission device 30, since the two-point modulation type frequency modulation device 10 with improved modulation accuracy is used, a high-quality transmission signal can be transmitted.

  FIG. 21 shows a configuration example of a wireless communication apparatus provided with the two-point modulation type frequency modulation apparatus of the present invention. The wireless communication device 40 includes a wireless transmission unit 41 including the two-point modulation type frequency modulation device 10 and the amplifier 31, a wireless reception unit 42 that performs predetermined reception processing such as demodulation processing of the reception signal, a transmission signal, and a reception signal. And a duplexer 43 and an antenna 25. Thereby, in the wireless transmission device 40, since the two-point modulation type frequency modulation device 10 with improved modulation accuracy is used, a high-quality transmission signal can be transmitted.

  The two-point modulation type frequency modulation device, the wireless transmission device, and the wireless communication device according to the present invention have the effect that the input timing difference between the two-point modulation can be reduced and the modulation accuracy can be improved, Effective for portable communication terminals such as mobile phones, wireless communication devices, notebook personal computers, mobile communication terminals, two-point modulation type frequency modulation devices incorporated in wireless base station communication devices, wireless transmission devices, and wireless communication devices. is there.

Block diagram of a two-point modulation type frequency modulation apparatus according to Embodiment 1 of the present invention The figure which shows the data of the delay amount coefficient stored in the storage table of the filter coefficient calculation part of the two-point modulation type frequency modulation apparatus shown in FIG. Block diagram of a digital filter of the two-point modulation type frequency modulation device shown in FIG. Output waveform diagram according to Embodiment 1 Output waveform diagram according to Embodiment 1 Output waveform diagram according to Embodiment 1 The figure which shows the delay adjustment interval which concerns on Embodiment 1. Output waveform diagram according to Embodiment 1 Output waveform diagram according to Embodiment 1 Frequency characteristics of digital filter FIG. 1 is a system block diagram of a wireless communication apparatus adopting a polar modulation transmission system in which the two-point modulation type frequency modulation apparatus shown in FIG. 1 is incorporated. Block diagram of a two-point modulation type frequency modulation apparatus according to Embodiment 2 of the present invention Block diagram of a digital filter of the two-point modulation type frequency modulation device shown in FIG. Block diagram of a two-point modulation type frequency modulation apparatus according to Embodiment 3 of the present invention Output waveform diagram according to Embodiment 3 Output waveform diagram according to Embodiment 3 Block diagram of a two-point modulation type frequency modulation apparatus according to Embodiment 4 of the present invention Block diagram of two-point modulation type frequency modulation apparatus according to Embodiment 5 of the present invention Frequency-gain characteristic diagram according to Embodiment 1 of the present invention Block diagram of radio transmitting apparatus according to Embodiment 6 of the present invention Block diagram of a radio communication apparatus according to Embodiment 6 of the present invention Schematic configuration diagram showing a conventional broadband modulation PLL

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 2 point | piece modulation type frequency modulation apparatus 11 PLL circuit 110 Voltage control oscillator 111 Frequency divider 112 Phase comparator 113 Loop filter 114,181 Adder 12 Signal input part 13 Frequency division ratio production | generation part 14 Digital-analog converter 15 Filter 16 Analog Digital converter 17 Filter coefficient calculation unit 17M Storage table 18 Digital filter 18A First digital filter 18B Second digital filter 180 Delay element 183, 184, 186, 187 Multiplier 185 Timing adjustment mode switching unit 20 Radio transmission device 21 Amplitude Phase separation unit 22 Amplitude modulation signal amplifier 24 High frequency power amplifier 25 Antenna 30 Wireless transmission device 40 Wireless communication device

Claims (7)

A frequency division ratio setting unit for setting a frequency division ratio based on the first digital baseband signal and the carrier wave signal;
Based on the frequency division ratio set by the frequency division ratio setting unit, the frequency divider that divides the input modulation signal, the phase of the frequency division signal output from the frequency divider, and the phase of the reference signal A phase comparator that outputs a signal corresponding to the phase difference, a loop filter that averages a signal output from the phase comparator, and a signal that is delay-adjusted to a signal output from the loop filter A signal adder that adds the two digital baseband signals, and a voltage controlled oscillator that receives a signal output from the signal adder and outputs a modulation signal having an oscillation frequency corresponding to the voltage of the input signal. A modulation signal output from the voltage controlled oscillator includes a PLL circuit input to the frequency divider;
A two-point modulation type frequency modulation device comprising:
In a timing adjustment mode for adjusting an input timing between two-point modulation, the first digital baseband signal and the second digital baseband signal obtained by inverting the first digital baseband signal Use
A delay amount coefficient calculation unit that calculates a delay amount coefficient,
Using the delay amount coefficient calculated by the delay amount coefficient calculation unit, the first, do one of the delay adjustment of the second digital baseband signal, the delay adjusted first digital baseband signal A delay adjustment unit that outputs the second digital baseband signal subjected to delay adjustment to the signal addition unit ;
Equipped with a,
The delay amount calculation unit includes:
A plurality of delay amount coefficients are held, and when the plurality of delay amount coefficients are sequentially supplied to the delay adjustment unit one by one, the signal amplitude output from the signal addition unit is the first and second digital By detecting the maximum value within the period of the signal amplitude by detecting in units of clocks over a period corresponding to one period of the baseband signal, sequentially performing the plurality of delay amount coefficients, Selecting a delay amount coefficient that minimizes the maximum value of the signal amplitude;
Two-point modulation type frequency modulation device.   2. The two-point modulation type frequency modulation apparatus according to claim 1, wherein the delay amount coefficient calculation unit includes a storage table for storing information on the plurality of delay amount coefficients. Each of the plurality of delay amount coefficients held in the delay amount coefficient calculating unit is a tap coefficient,
The delay adjustment unit shifts the phase of either the first digital baseband signal or the second digital baseband signal using a tap coefficient corresponding to the delay amount coefficient selected by the delay amount coefficient calculation unit. 3. The two-point modulation type frequency modulation apparatus according to claim 1, wherein the two-point modulation type frequency modulation apparatus is a digital filter that performs the delay adjustment.   4. The apparatus according to claim 1, further comprising a signal inverting unit that generates the second digital baseband signal by inverting the first digital baseband signal. The two-point modulation type frequency modulation device described in 1.   The signal inversion unit is provided in a signal input unit that supplies the first digital baseband signal and the second digital baseband signal, or in the delay adjustment unit. 2-point modulation type frequency modulation device.   The delay adjustment unit may be configured to supply the first digital baseband signal to the PLL circuit, the second digital baseband signal, or the first digital baseband signal and the second digital. 6. The two-point modulation type frequency modulation apparatus according to claim 1, wherein the two-point modulation type frequency modulation apparatus is provided in both of the supply paths of the baseband signals. An amplitude phase separation unit that generates an amplitude component signal and a phase component signal from an input signal;
An amplitude modulation signal amplifier that amplifies the amplitude component signal input from the amplitude phase separation unit and outputs the amplified amplitude component signal;
The two-point modulation type frequency modulation apparatus according to any one of claims 1 to 6, wherein modulation is performed using the phase component signal input from the amplitude phase separation unit, and a modulation signal is output.
A high frequency signal that generates a transmission signal by amplifying a modulation signal output from the two-point modulation type frequency modulation device using a power supply voltage set according to the amplitude component signal amplified by the amplitude modulation signal amplifier A power amplifier;
A wireless transmission device comprising:

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