JP3481165B2 - Digital modulator - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital modulator, and more particularly to a digital modulator for performing quadrature digital modulation with a multiplication table.

[0002]

2. Description of the Related Art A conventional digital modulator, as shown in FIG. 11, has an oscillator for outputting a carrier wave and a multiplication for multiplying the in-phase baseband signal and the quadrature baseband signal converted into digital signals by the respective carrier waves. And a D / A (digital / analog) converter for converting the modulated digital signal into an analog signal and outputting it as a modulated wave. Further, Japanese Patent No. 2510490 discloses a digital modulator that does not require a carrier wave oscillator or a multiplier.

[0003]

However, in the above-mentioned conventional digital modulator requiring the digital multiplier and the adder, the processor for digital signal processing having the digital multiplier and the adder becomes large in scale, and the digital modulation is performed. There is a problem that the device becomes expensive. Further, the digital modulator disclosed in Japanese Patent No. 2510490 has a problem that the phase relationship of carrier waves cannot be changed.

The first object of the present invention is to solve the above conventional problems and to realize a digital modulator having a small circuit scale by using only inexpensive and general-purpose components without using a multiplier or an adder. The purpose of.

Further, it is possible to switch the phase relationship of the carrier wave without using the carrier wave oscillator, the multiplier or the adder, and switch the phase relationship of the in-phase and quadrature baseband signal data in the output quadrature modulated wave data. A second object is to realize a modulator.

[0006]

In order to solve the above problems, according to the present invention, a digital modulator counts clock signals at sampling frequencies of an in-phase baseband signal and a quadrature baseband signal and outputs a count value. Counting means, the in-phase baseband signal data and the count value are used as read addresses, and carrier waves having a frequency that is a natural number multiple of the counting repetition frequency of the counting means are quantized for each sampling period to the in-phase baseband. The first storage means stores the first modulated wave data multiplied by the data pattern of the signal data, the quadrature baseband signal data, the count value, and the phase relationship between the carrier waves of the in-phase baseband signal and the quadrature baseband signal. The carrier phase selection signal to be selected is used as a read address, and (+) is added to the carrier phase of the in-phase baseband signal. / 2) and carrier wave data having phases different by (-π / 2) are multiplied by a data pattern of quadrature baseband signal data to store second modulated wave data, and first and second storage means. The adding means for adding the modulated wave data output from the storage means and outputting the orthogonal modulated wave data.

With this configuration, it is possible to output the quadrature modulated wave data quadrature-modulated by the carrier without using a multiplier, and it is possible to easily switch the phase of the carrier.

Further, counting means for counting clocks of sampling frequencies of the in-phase baseband signal and the quadrature baseband signal and outputting a count value, in-phase baseband signal data, quadrature baseband signal data, count value and carrier phase selection. The signal and the read address, the quadrature modulated wave data calculated from the data pattern of the in-phase baseband signal data and the data pattern of the quadrature baseband signal data is stored for each phase relationship of the carrier wave selected by the carrier wave phase selection signal, Storage means for outputting quadrature modulated wave data according to each read address value is provided.

With this configuration, it is possible to output quadrature-modulated wave data that has been quadrature-modulated without the need for an adder.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is a counting means for counting clock signals of sampling frequencies of an in-phase baseband signal and a quadrature baseband signal and outputting a count value, and an in-phase baseband signal. The signal data and the count value are used as read addresses, and carrier data having a frequency that is a natural number multiple of the counting repetition frequency of the counting means is quantized for each sampling cycle, and the data pattern of the in-phase baseband signal data is added to the carrier data. First storage means for storing the multiplied first modulated wave data, quadrature baseband signal data, the count value, and carrier phase selection for selecting the phase relationship between the carrier waves of the in-phase baseband signal and the quadrature baseband signal (+ Π / 2) for the phase of the carrier wave of the in-phase baseband signal, with the signal as the read address
And carrier data with a phase difference of (-π / 2),
Quadrature modulated waves by adding the modulated wave data output from the first and second memory means with the second storage means storing the second modulated wave data multiplied by the data pattern of the quadrature baseband signal data. An operation of outputting quadrature-modulated wave data obtained by quadrature-modulating in-phase and quadrature baseband signal data in a phase relationship of a carrier wave according to a carrier-wave phase selection signal, the digital modulator including an adding means for outputting data. Have.

According to a second aspect of the present invention, in the digital modulation apparatus according to the first aspect, the in-phase baseband signal data, the count value, and the carrier phase are replaced by the first storage means. The selection signal is used as the read address, and (+
Storage means is provided for storing first modulated wave data obtained by multiplying carrier wave data having a phase difference of (π / 2) and (−π / 2) by a data pattern of in-phase baseband signal data, and the second storage means. Instead of the above, the storage means is provided for storing the second modulated wave data obtained by multiplying the data pattern of the quadrature baseband signal data by the carrier data by using the quadrature baseband signal data and the count value as the read address. The function of outputting the modulated wave data obtained by modulating the in-phase baseband signal data from the table according to the phase relationship of the carrier wave according to the carrier wave phase selection signal.

According to a third aspect of the present invention, in the digital modulation apparatus according to the first aspect, the in-phase baseband signal data, the count value, and the carrier wave phase are replaced with the first storage means. The selection signal and the read address are used as a read address, and storage means is provided for storing first modulated wave data obtained by multiplying the data pattern of the in-phase baseband signal data by the carrier data for each phase relationship of the carrier to be selected, and the second storage. Instead of the means, the quadrature baseband signal data, the count value, and the carrier phase selection signal are used as read addresses,
Storage means is provided for storing second modulated wave data obtained by multiplying the data pattern of the quadrature baseband signal data by the carrier wave data, for each phase relationship of the carrier wave to be selected, and the phase relationship corresponding to the carrier wave phase selection signal. The quadrature modulated wave data obtained by quadrature modulating the in-phase and quadrature baseband signal data is output from the table.

According to a fourth aspect of the present invention, in the digital modulator according to the first aspect, the count value is converted so that the phase of the carrier wave has a phase relationship selected by the carrier wave phase selection signal. Counting value conversion means is provided, and instead of the second storage means, the converted count value output from the counting value conversion means and the quadrature baseband signal data are used as read addresses, and the quadrature baseband signal data Second data pattern multiplied by carrier wave data
A storage means for storing the modulated wave data of is provided, and the function of outputting the quadrature modulated wave data obtained by quadrature modulating the in-phase and quadrature baseband signal data in the phase relationship of the carrier wave according to the carrier wave phase selection signal from the table Have.

According to a fifth aspect of the present invention, in the digital modulation apparatus according to the second aspect, the count value is converted so that the phase of the carrier wave has a phase relationship selected by the carrier wave phase selection signal. A count value converting means for converting the count value converting means and the in-phase baseband signal data output from the count value converting means into read addresses, instead of the first storage means. First data pattern multiplied by carrier data
A storage means for storing the modulated wave data of is provided, and the function of outputting the quadrature modulated wave data obtained by quadrature modulating the in-phase and quadrature baseband signal data in the phase relationship of the carrier wave according to the carrier wave phase selection signal from the table Have.

According to a sixth aspect of the present invention, counting means for counting clocks of sampling frequencies of the in-phase baseband signal and the quadrature baseband signal and outputting a count value, in-phase baseband signal data and quadrature base The band signal data, the count value, and the carrier phase selection signal are used as read addresses, and the data pattern of the in-phase baseband signal data and the data of the quadrature baseband signal data are set for each phase relationship of the carrier selected by the carrier phase selection signal. It is a digital modulator provided with a storage means for storing quadrature modulated wave data calculated in advance from a pattern and outputting the quadrature modulated wave data according to each read address value, in the phase relationship of the carrier wave according to the carrier wave phase selection signal. Quadrature modulated wave data obtained by quadrature modulating the in-phase and quadrature baseband signal data is tested. It has the effect of outputting from a cable.

FIG. 1 shows an embodiment of the present invention.
A detailed description will be given with reference to FIGS.

(First Embodiment) In the first embodiment of the present invention, the in-phase modulated wave data table is read by using the in-phase baseband signal data and the clock count value as the read address, and the quadrature baseband signal data is read. This is a digital modulator that reads a quadrature modulated wave data table by using a clock count value and a carrier wave phase selection signal as a read address and adds both modulated wave data to obtain quadrature modulated wave data.

FIG. 1 is a functional block diagram showing the configuration of a digital modulator according to the first embodiment of the present invention. In FIG. 1, a digital modulator 1 is a device for quadrature modulating an in-phase baseband signal and a quadrature baseband signal in a specified phase relationship. In-phase baseband signal data 10
Is data obtained by sampling the in-phase baseband signal at the sampling frequency F _s . The quadrature baseband signal data 11 is data obtained by sampling the quadrature baseband signal at the sampling frequency F _s .

The carrier phase selection signal 12 has an orthogonal relationship.
The phase relationship of the carrier waves of in-phase and quadrature baseband signals
This is the signal to select. Clock 13 is the sampling frequency
Number F _sThe clock is oscillating at. The counting means 14 is
The cycle of counting the clock 13 and repeating the count value (below
Below, the counting repetition cycle) T is the sampling cycle T_s(= 1 /
F_s) Times N (T = NT_s) Is a counting means. Counting
The value 15 is output from the counting means 14 and the sampling point
It is a count value indicating the temperature.

The first storage means 16 uses the in-phase baseband signal data 10 and the count value 15 as read addresses, and is n times (n = 1, n) the counting repetition frequency F (= 1 / T) of the counting means 14.
Storage means for storing modulated wave data obtained by multiplying carrier data having a frequency f _c of 2, 3, ...) Quantized at each sampling point by a data pattern of in-phase baseband signal data. The second storage means 17 is
The quadrature baseband signal data 11, the count value 15, and the carrier phase selection signal 12 are used as read addresses, and the carrier data multiplied by the in-phase baseband signal data is + π / 2,
The storage means stores modulated wave data that is obtained by multiplying the carrier wave data shifted by −π / 2 and the data pattern of the orthogonal baseband signal data.

The adding means 18 adds the first modulated wave data output from the first storage means 16 and the second modulated wave data output from the second storage means 17, and obtains the orthogonal modulated wave data.
It is an addition means for outputting 19. The D / A converting means 20 is a D / A converting means for D / A converting the quadrature modulated wave data 19 which is a digital signal. The quadrature modulated wave 21 is a quadrature modulated wave converted into an analog signal by the D / A conversion means 20.

The operation of the digital modulation apparatus of the first embodiment of the present invention configured as above will be described with reference to FIG. 1 and Table 1.

[0023]

[Table 1]

Table 1 shows the read address of the second storage means 17.
3 is a table showing an example of stored modulated wave data.
Each carrier wave data c of the phase relation to be selected₁, u,
c₂, _u, ..., c_I,_uAnd orthogonal baseband signal data d_v
Modulated wave data m multiplied by_i,_u,_v(M_i,_u,_v= C_i,_u× d_v
  , I = 1, 2, ..., I, u = 1, 2, ..., N, v =
1, 2, ..., V) are stored in the memory and read
Carrier wave phase selection signal S input as a part of
_i(S_i= 1, 2, ..., I), the phase relationship is arbitrarily set to 1
You can choose one.

Table 1 shows the selectable carrier wave phase S
_{An example is shown in which i} is either advanced or delayed (1 bit), the number of sampling points P _u is 16 points (4 bits), and the quantization pattern d _v of orthogonal baseband signal data is 4 patterns (2 bits). ing.

The counting means 14 counts the clock 13 oscillating at the sampling frequency F _s , and counts 15 indicating sampling points P _u = P ₁ , P ₂ , ..., P _N (N is the number of sampling points). Is being output. The repetition cycle T of this count value is N times the sampling cycle T _s , that is, one cycle with N clocks 13.

The in-phase baseband signal data 10 and the sampling point P are stored in the read address of the first storage means 16.
_The count value 13 indicating _u is input. This first storage means 16
9a, carrier data c _u (c _u sampled at each sampling point P _u is stored in the memory of FIG.
= C ₁ , c ₂ , ..., C _N ) and the data patterns d ₁ , d ₂ , ..., d _V (V is the number of bit patterns) of the in-phase baseband signal data, the modulated wave data m _u , _v ( _Mu , _v = c
_u × d _v ) are stored in the order of sampling points.

Since the counting means 14 counts the count value 15 for each sampling period T _s , by making this count value 15 a part of the read address of the storage means, the sampling point P _u indicated by the current count value. Carrier data c _{u at}
The modulated wave data m _u , _v multiplied by can be read in order. At the same time, the current baseband signal data d _v input as a part of the read address from the modulated wave data multiplied by the data patterns d ₁ , d ₂ , ..., D _{V of} the in-phase baseband signal data. The modulated wave data m _u , _v multiplied by can be selected and read. Further, the carrier frequency f _c is, n times the counting repetition frequency F of the counting means 14 (n = 1,2,3, ...) and to order that (fc = nF), the carrier wave becomes discontinuous during repetitive counting In this case, modulated wave data obtained by modulating baseband signal data with continuous carrier wave data can be obtained.

In quadrature modulation, the carrier wave multiplied by the in-phase baseband signal and the carrier wave multiplied by the quadrature baseband signal have a quadrature relationship in which the phases are different by (π / 2). As shown in FIG. 7, two carrier waves in an orthogonal relationship lead the phase of the carrier wave of the in-phase baseband signal by (π / 2) with respect to the phase of the carrier wave of the in-phase baseband signal. When the phase of the carrier wave of the quadrature baseband signal is delayed by (π / 2) with respect to the phase of the carrier wave of the in-phase baseband signal as shown in FIG. There are two topological relationships.

Therefore, in order to arbitrarily select the above two phase relationships, in addition to the orthogonal baseband signal data 11 and the count value 15, the phase relationship of the carrier wave is selected for the read address of the second storage means 17. The carrier phase selection signal 12 to be input is input. Then, in the memory of the second storage means 17, as shown in FIG. 9B, modulated wave data obtained by multiplying the (+ π / 2) phase-shifted carrier data by the data pattern of the quadrature baseband signal data (see Table 1). The upper half, data in the region of S _i = S ₁ ) and the modulated wave data ((π / 2) phase-shifted carrier data and the data pattern of the quadrature baseband signal data as shown in FIG. In Table 1, the lower half, data of the area of S _i = S ₂ ) is stored. Any one of the modulated wave data can be arbitrarily selected and read by the carrier phase selection signal 12.

The shaded area in Table 1 is an example in which the modulated wave data to be read is selected from the modulated wave data stored in the memory by each signal input as the read address. In this example, the phase of the carrier wave is advanced, and the sampling point indicated by the count value 15 is P ₂ and the orthogonal baseband signal data is (10).
First, the region S ₁ (0) in which the carrier data of the phase relationship selected by the carrier phase selection signal 12 is multiplied is selected. At the same time, the area P ₂ (0001) of the current sampling point indicated by the count value 15 is selected, and the current orthogonal baseband signal data is further multiplied by the orthogonal baseband signal data input to the read address. The area d ₃ (10) is selected, and the modulated wave data m ₁ , ₂ , ₃ stored in the read addresses corresponding to all the above areas are read. This modulated wave data m ₁ , ₂ , ₃ is
The carrier data c ₁ , ₂ is a value obtained by multiplying the quadrature baseband signal data d ₃ , and the carrier data c ₁ , ₂ is a sampling point for a carrier having a phase relationship selected by the carrier phase selection signal (S ₁ ). This is the data sampled at P ₂ .

Next, the adding means 18 adds the modulated wave data read from the first memory means 16 and the second memory means 17, and outputs orthogonal modulated wave data 19.

Finally, the D / A conversion means 20 D / A converts the quadrature modulated wave data 19, which is digital data, and outputs a quadrature modulated wave 21 as an analog signal.

As described above, in the first embodiment of the present invention, the digital modulation device reads the in-phase modulated wave data table using the in-phase baseband signal data and the clock count value as the read address to read the quadrature baseband signal. The quadrature modulated wave data table is read using the data, clock count value, and carrier phase selection signal as read addresses, and both modulated wave data are added to obtain quadrature modulated wave data. It is possible to realize a digital modulator having a small circuit scale with inexpensive and general-purpose components that are not required, and to change arbitrarily the phase relationship between the in-phase and quadrature baseband signal data in the output quadrature-modulated wave data.

(Second Embodiment) In the second embodiment of the present invention, the in-phase baseband signal data, the clock count value, and the carrier phase selection signal are used as the read address, and (π /
This is a digital modulator that reads in-phase modulated wave data having a different phase by 2) and reads the quadrature modulated wave data by using the quadrature baseband signal data and the clock count value as a read address.

The second embodiment of the present invention is different from the first embodiment in that in the digital modulator 1,
The phase of the carrier of the quadrature baseband signal data 11 is selected by the carrier phase selection signal 12 to be a lead phase or a lag phase, and the phase relationship between in-phase and quadrature baseband signal data in quadrature modulation is arbitrarily switched. 2 is that the phase of the carrier of the in-phase baseband signal data 10 is selected by the carrier phase selection signal 12 to switch the phase relationship between the in-phase and quadrature baseband signal data. There are no other differences in other respects.

FIG. 2 is a functional block diagram of a digital modulator according to the second embodiment of the present invention. In FIG. 2, the first storage means 22 stores in-phase baseband signal data.
10, the count value 15 and the carrier phase selection signal 12 are used as the read address, and with respect to the carrier phase of the quadrature baseband signal,
This is a memory that stores a table of first modulated wave data obtained by multiplying carrier data having a phase difference of (+ π / 2) and (−π / 2) by the data pattern of the in-phase baseband signal data 10. The second storage means 23 is a memory that stores a table of second modulated wave data in which the orthogonal baseband signal data and the count value are used as the read address and the data pattern of the orthogonal baseband signal data is multiplied by the carrier wave data. .

The digital modulator of the second embodiment of the present invention changes the phase of the carrier wave of the in-phase baseband signal, and is used when it is necessary to fix the phase of the carrier wave of the quadrature baseband signal. it can.

As described above, in the second embodiment of the present invention, the digital modulator uses the in-phase baseband signal data, the clock count value, and the carrier phase selection signal as the read address, and the phase is shifted by (π / 2). Different in-phase modulation wave data is read, and quadrature baseband signal data and clock count values are used as read addresses to read the quadrature modulation wave data, so a multiplier and a carrier wave oscillator are not required, and it is inexpensive and versatile. It is possible to realize a digital modulator having a small circuit scale with various components, and to arbitrarily change the phase relationship between the in-phase and quadrature baseband signal data in the output quadrature modulated wave data.

(Third Embodiment) In the third embodiment of the present invention, the in-phase modulated wave data is read by using the in-phase baseband signal data, the clock count value, and the carrier phase selection signal as the read address, and the quadrature base signal is read. This is a digital modulation device that reads quadrature modulated wave data using band signal data, a clock count value, and a carrier phase selection signal as a read address.

The third embodiment of the present invention differs from the first and second embodiments in that the digital modulator 1,
In 2, the carrier phase selection signal 12 selects the phase of the carrier of either in-phase or quadrature baseband signal data, the lead phase or the lag phase, and the phase relationship between the in-phase and quadrature baseband signal data in quadrature modulation is selected. However, in the digital modulator 3 in the third embodiment, the phase relationship of both carriers of the in-phase and quadrature baseband signal data is switched by the carrier phase selection signal 12, and the in-phase and quadrature baseband signal data in quadrature modulation is switched. The point is to switch the phase relationship of.

FIG. 3 is a functional block diagram showing the configuration of a digital modulator according to the third embodiment of the present invention. As shown in FIG. 3, in the digital modulation device 3, the counting means 14, the adding means 18, D of the digital modulation device 1 shown in FIG.
In-phase baseband signal data in addition to the A / A conversion means 20
The first modulated wave data obtained by multiplying the carrier wave data by the data pattern of the in-phase baseband signal data 10 is calculated and stored for each phase relationship of the carrier wave to be selected, using 10, the count value 15 and the carrier wave phase selection signal 12 as the read address. The first modulating means 24 and the second modulated wave obtained by multiplying the carrier pattern by the data pattern of the quadrature baseband signal data 11 by using the quadrature baseband signal data 11, the count value 15, and the carrier phase selection signal 12 as read addresses. The second storage means 25 is provided for calculating and storing data for each phase relationship of the selected carrier waves.

As described above, in the third embodiment of the present invention, the digital modulation device reads the in-phase modulated wave data by using the in-phase baseband signal data, the clock count value and the carrier phase selection signal as the read address. Since the quadrature modulated wave data is read using the quadrature baseband signal data, the clock count value, and the carrier wave phase selection signal as the read address, a multiplier and a carrier wave oscillator are not required, and the circuit is an inexpensive general-purpose component. A small-scale digital modulator can be realized, and the phase relationship between in-phase and quadrature baseband signal data can be arbitrarily changed in the output quadrature-modulated wave.

(Fourth Embodiment) In the fourth embodiment of the present invention, conversion of a clock count value is instructed by a carrier phase selection signal, and the converted clock count value and quadrature baseband signal data are read out. It is a digital modulator that reads out quadrature modulated wave data as an address.

The difference between the fourth embodiment of the present invention and the first to third embodiments is that the digital modulators 1 to
In 3, the table is switched by the carrier phase selection signal 12 to switch the phase relationship. However, in the digital modulator 4 in the fourth embodiment, the carrier phase selection signal 12 is used.
The point is that the conversion of the clock coefficient value is instructed by and the phase relationship between the in-phase and quadrature baseband signal data in quadrature modulation is switched.

FIG. 4 is a functional block diagram showing the configuration of a digital modulator according to the fourth embodiment of the present invention. As shown in FIG. 4, in the digital modulation device 4, the counting means 14, the addition means 18, D of the digital modulation device 1 shown in FIG.
In addition to the A / A conversion means 20, a count value conversion means 26 for converting the count value 15 so that the phase of the carrier wave becomes the phase relationship selected by the carrier wave phase selection signal 12, and the count value conversion means 26 outputs the count value. Second storage means for storing the second modulated wave data obtained by multiplying the data pattern of the orthogonal baseband signal data 11 by the carrier wave data, using the converted count value 27 and the orthogonal baseband signal data 11 as read addresses.
Equipped with 28.

FIG. 10a shows the in-phase baseband signal data.
The carrier wave data multiplied by 10 is shown. The count value 15 output from the counting means 14 is input to the read address of the first storage means 16, and the sampling point indicated by the count value 15 starts from P ₁ in this case.
On the other hand, FIGS. 10b and 10c show carrier wave data to be multiplied by the quadrature baseband signal data 11. At the read address of the second storage means 28, the count value conversion means 26
The count value 27 converted by is input, the converted count value 27 is offset as shown in FIG. 10b, and the counting start is the phase of the carrier wave (+ π / 2).
It starts from the phase shift. By doing so, the carriers of the in-phase and quadrature baseband signal data are in a quadrature relationship, and in this case, the lead phase relationship shown in FIG. 7 can be achieved. When the offset value is changed, the phase of the carrier wave is (-π /, as shown in FIG. 10c).
2) It starts from the phase shift, and in this case, the relationship of the delay phase shown in FIG. 8 can be obtained. Count conversion means 26
In addition to the count value 15, the carrier phase selection signal 12 is input.Therefore, by switching the value to be offset by the carrier phase selection signal 12, the phase relationship of the carrier is selected and the in-phase and It is possible to switch the phase relationship of the quadrature baseband signal data.

In the fourth embodiment, as shown in FIG.
As shown in FIGS. 10b and 10c, the carrier data to be multiplied by the in-phase and quadrature baseband signal data can be the same, and the in-phase baseband signal data and the quadrature baseband signal data have the same number of bits, If the data patterns are the same, the modulated wave data stored in the first storage means 16 and the second storage means 28 can be the same data. That is, it is possible to use storage means having the same storage content.

With the above-mentioned configuration, a digital modulator having a small circuit scale can be realized with inexpensive general-purpose components without the need for a multiplier or a carrier wave oscillator, and the in-phase quadrature modulated waves can be output in phase. Also, it is possible to arbitrarily change the phase relationship between the orthogonal baseband signal data.

(Fifth Embodiment) In the fifth embodiment of the present invention, a count value is converted by a carrier phase selection signal, and the converted count value and the in-phase baseband signal data are used as a read address. It is a digital modulator for reading modulated wave data.

In the digital modulator 4, the carrier phase of the quadrature baseband signal data 11 is selected by the carrier phase selection signal 12 from the lead phase as shown in FIG. 7 or the lag phase as shown in FIG. To switch the phase relationship between the in-phase and quadrature baseband signal data in.
In the digital modulator 5 of the embodiment, the phase of the carrier of the in-phase baseband signal data 10 is selected by the carrier phase selection signal 12 and the phase relationship between the in-phase and quadrature baseband signal data is switched.

FIG. 5 is a digital modulator showing the structure of the fifth embodiment. As shown in FIG. 5, in the digital modulation device 5, in addition to the counting means 14, the addition means 18, and the D / A conversion means 20 of the digital modulation device 2 shown in FIG.
Count value conversion means 26 for converting the count value 15 so that the phase of the carrier wave becomes the phase relationship selected by the carrier wave phase selection signal 12, and the converted count value 27 output from the count value conversion means 26 and in-phase base The band signal data 10 is used as a read address, and the first storage means 29 is provided for storing the first modulated wave data obtained by multiplying the data pattern of the in-phase baseband signal data 10 by the carrier wave data.

In the fifth embodiment, the first storage means 29
The count value 27 converted by the count value converting means 26 is input to the read address of the carrier wave. The converted count value 27 shifts the phase of the carrier wave by (+ π / 2) or (−π / 2). As offset. The count conversion means 26 receives the carrier phase selection signal 12 in addition to the count value 15,
The carrier wave phase selection signal 12 switches the offset value to select the carrier wave phase relationship and switch the phase relationship between in-phase and quadrature baseband signal data in quadrature modulation.

Like the digital modulator 4, the digital modulator 5 has the same number of bits in the in-phase baseband signal data 10 and the quadrature baseband signal data 11 and the same data pattern. The modulated wave data stored in 29 and the second storage means 23 can be the same data. That is, it is possible to use storage means having the same storage content.

With the above-described structure, a digital modulator having a small circuit scale can be realized with inexpensive general-purpose components without the need for a multiplier or a carrier wave oscillator, and output quadrature modulated wave data. It is possible to arbitrarily change the phase relationship between the in-phase and quadrature baseband signal data.

(Sixth Embodiment) In the sixth embodiment of the present invention, the in-phase baseband signal data, the quadrature baseband signal data, the count value and the carrier phase selection signal are used as read addresses, and the quadrature modulated wave data is used. Is a digital modulation device for reading out.

FIG. 6 is a functional block diagram showing the configuration of a digital modulator according to the sixth embodiment of the present invention. As shown in FIG. 6, in the digital modulation device 6, in addition to the counting means 14 of the digital modulation device 1 shown in FIG. 1, in-phase baseband signal data 10 and quadrature baseband signal data are added.
11, the count value 15 and the carrier phase selection signal 12 are used as the read address, and the data pattern of the in-phase baseband signal data 10 and the data pattern of the quadrature baseband signal data 11 are selected for each phase relationship selected by the carrier phase selection signal 12. The storage means 30 stores the calculated quadrature modulated wave data and outputs the quadrature modulated wave data 31 in accordance with each read address value. Further, the D / A conversion means 32 D / A converts the quadrature modulated wave data 31, which is digital data, and outputs the quadrature modulated wave 21 as an analog signal.

The quadrature modulated wave data 31 is calculated from the data pattern of the in-phase baseband signal data 10 and the data pattern of the quadrature baseband signal data 11, but as shown in FIG. 7, with respect to the phase of the carrier wave of the in-phase baseband signal. Then, a case where the phase of the carrier wave of the quadrature baseband signal is advanced by (π / 2) and a case where it is delayed by (π / 2) as shown in FIG. 8 are calculated and stored in the storage means 30. Therefore, it is possible to switch the phase relationship between the in-phase and quadrature baseband signal data in the quadrature modulation by selecting the lead phase relationship or the lag phase relationship by the carrier phase selection signal 12.

With the above-mentioned configuration, neither a multiplier, a carrier wave oscillator, nor an adder is required,
It is possible to realize a digital modulator having a small circuit scale with inexpensive general-purpose components, and to provide a device capable of arbitrarily switching the phase relationship between in-phase and quadrature baseband signal data in output quadrature-modulated wave data.

[0060]

As is apparent from the above description, according to the present invention, the digital modulation device is provided with the counting means for counting the clocks of the sampling frequencies of the in-phase baseband signal and the quadrature baseband signal and outputting the count value. Using the in-phase baseband signal data and the count value as the read address, the carrier data having a frequency that is a natural multiple of the counting repetition frequency of the counting means is quantized for each sampling period and the data pattern of the in-phase baseband signal data is multiplied. And a carrier phase selection signal for selecting the phase relationship between the quadrature baseband signal data and the count value and the phase of the carrier of the quadrature baseband signal as a read address. (+ Π / 2) and (-π / 2) for the carrier phase of the baseband signal
The second storage means storing the second modulated wave data obtained by multiplying the carrier wave data having a different phase by the data pattern of the quadrature baseband signal data, and the modulated wave data output from the first and second storage means. Since it is configured to include an adding unit that adds and outputs the quadrature modulated wave data, it is possible to output the quadrature modulated wave data quadrature modulated by the carrier without using a multiplier, and to change the phase of the carrier. The effect that it can be easily switched arbitrarily is obtained.

The in-phase baseband signal data, the quadrature baseband signal data, the count value, and the carrier phase selection signal are used as the read address, and the in-phase baseband signal data of the in-phase baseband signal data is selected for each phase relationship of the carrier selected by the carrier phase selection signal. Since the quadrature modulated wave data calculated from the data pattern and the data pattern of the quadrature baseband signal data is stored and the storage means for outputting the quadrature modulated wave data according to each read address value is provided, an adder is not required. The effect that quadrature-modulated wave data that is quadrature-modulated can be output is obtained.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing a configuration of a digital modulation device according to a first embodiment of the present invention,

FIG. 2 is a functional block diagram showing a configuration of a digital modulation device according to a second embodiment of the present invention,

FIG. 3 is a functional block diagram showing a configuration of a digital modulation device according to a third embodiment of the present invention,

FIG. 4 is a functional block diagram showing the configuration of a digital modulation device according to a fourth embodiment of the present invention,

FIG. 5 is a functional block diagram showing a configuration of a digital modulation device according to a fifth embodiment of the present invention,

FIG. 6 is a functional block diagram showing a configuration of a digital modulation device according to a sixth embodiment of the present invention,

FIG. 7 is an explanatory diagram when the phase relationship of carrier waves is a π / 2 lead phase relationship,

FIG. 8 is an explanatory diagram in the case where the carrier wave phase relationship is a π / 2 delay phase relationship,

FIG. 9 is an explanatory diagram of carriers of in-phase and quadrature baseband signal data, a: carrier of in-phase baseband signal b: carrier of quadrature baseband signal (+ π / 2 phase shift) c: carrier of quadrature baseband signal (−) π / 2 phase shift)

FIG. 10 is an explanatory diagram of carriers of in-phase and quadrature baseband signal data, a: carrier of in-phase baseband signal b:
Carrier wave of quadrature baseband signal (+ π / 2 phase shift) c: Carrier wave of quadrature baseband signal (−π / 2 phase shift)

FIG. 11 is a block diagram showing a configuration of a conventional digital modulator.

[Explanation of symbols]

1 Digital modulator 1 2 Digital modulator 2 3 Digital modulator 3 4 Digital modulator 4 5 Digital modulator 5 6 Digital modulator 6 10 In-phase baseband signal data 11 Orthogonal baseband signal data 12 Carrier phase selection signal 13 clock 14 Counting means 15 Count value 16 First storage means 17 Second storage means 18 means of addition 19 Quadrature modulated wave data 20 D / A conversion means 21 Quadrature modulated wave 22 First storage means 23 Second storage means 24 First storage means 25 Second storage means 26 Count value conversion means 27 Converted count value 28 Second storage means 29 First storage means 30 storage means 31 Quadrature modulated wave data 32 D / A conversion means

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiteru Kobayashi 4-3 Tsunashima-higashi, Kohoku-ku, Yokohama-shi, Kanagawa Matsushita Communication Industrial Co., Ltd. (56) Reference JP-A-4-252634 (JP, A) ) JP-A-4-238439 (JP, A) JP-A-10-164158 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04L 27/20

Claims (6)

(57) [Claims] 1. A counting means for counting a clock signal of a sampling frequency of an in-phase baseband signal and a quadrature baseband signal and outputting a count value, the in-phase baseband signal data and the count value as read addresses, and the count. Carrier data having a frequency that is a natural multiple of the counting repetition frequency of the means is quantized for each sampling period,
First storage means for storing first modulated wave data multiplied by a data pattern of in-phase baseband signal data, quadrature baseband signal data, the count value, and carriers of the in-phase baseband signal and the quadrature baseband signal The carrier phase selection signal for selecting the phase relationship of the carrier frequency is used as a read address, and the carrier data having a phase difference of (+ π / 2) and (−π / 2) with respect to the carrier phase of the in-phase baseband signal is added to the orthogonal baseband. Second storage means for storing second modulated wave data multiplied by the data pattern of the signal data and modulated wave data output from the first and second storage means are added to output orthogonal modulated wave data. A digital modulation device comprising: 2. In place of the first storage means, the in-phase baseband signal data, the count value and the carrier phase selection signal are used as read addresses, and (+ π) with respect to the carrier phase of the quadrature baseband signal. / 2) and (-π /
2) Storage means for storing first modulated wave data obtained by multiplying carrier wave data having a different phase by a data pattern of in-phase baseband signal data is provided, and instead of the second storage means, quadrature baseband signal data is provided. 2. The digital device according to claim 1, further comprising storage means for storing second modulated wave data obtained by multiplying the data pattern of the quadrature baseband signal data by the carrier wave data, using the count value and the count value as a read address. Modulator. 3. The in-phase baseband signal data, the count value, and the carrier phase selection signal are used as read addresses instead of the first storage means, and the data pattern of the in-phase baseband signal data is multiplied by the carrier data. Done first
Storage means for storing the modulated wave data of is stored for each phase relation of the selected carrier wave, and instead of the second storage means,
The quadrature baseband signal data, the count value, and the carrier phase selection signal are used as read addresses, and the second modulated wave data obtained by multiplying the data pattern of the quadrature baseband signal data by the carrier data is stored for each phase relationship of the carrier to be selected. 2. The digital modulation device according to claim 1, further comprising storage means. 4. A count value conversion means for converting the count value is provided so that the phase of the carrier wave has a phase relationship selected by the carrier wave phase selection signal, and the count value is replaced with the second storage means. The converted count value output from the conversion means and the quadrature baseband signal data are used as read addresses, and storage means is provided for storing second modulated wave data obtained by multiplying the data pattern of the quadrature baseband signal data by the carrier wave data. The digital modulation device according to claim 1, wherein 5. A count value conversion means for converting the count value is provided so that the phase of the carrier wave has a phase relationship selected by the carrier wave phase selection signal, and the count value is replaced with the count value conversion means. The converted count value output from the conversion means and the in-phase baseband signal data are used as read addresses, and a storage means is provided for storing first modulated wave data obtained by multiplying the data pattern of the in-phase baseband signal data by the carrier wave data. The digital modulator according to claim 2, wherein 6. A counting means for counting clocks of sampling frequencies of the in-phase baseband signal and the quadrature baseband signal and outputting a count value, in-phase baseband signal data, quadrature baseband signal data, the count value and carrier phase. The selection signal and the read address, for each phase relationship of the carrier selected by the carrier phase selection signal,
Storage means for storing the quadrature modulated wave data calculated in advance from the data pattern of the in-phase baseband signal data and the data pattern of the quadrature baseband signal data, and outputting the quadrature modulated wave data according to each read address value. Characteristic digital modulator.