JP3608765B2 - Frequency synthesizer device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention can frequency-convert a relatively low frequency signal to a higher frequency output band signal and expand its bandwidth, and is suitable for switching an output band signal of the expanded bandwidth at high speed. The present invention relates to a frequency synthesizer device, and more particularly to a frequency synthesizer device suitable for use in a frequency hopping spread spectrum communication system.
[0002]
[Prior art]
The frequency hopping spread spectrum communication system requires a frequency synthesizer device that can switch the frequency at high speed according to various hopping patterns. 2. Description of the Related Art Conventionally, a device using a phase locked loop (PLL) synthesizer has been widely used as a device for switching frequencies. However, in this PLL system, the response of the loop filter is slow, and it is difficult to obtain a sufficiently fast switching time. Therefore, it has been proposed to use a direct digital synthesizer (DDS) capable of switching the frequency at high speed, but this direct digital synthesizer can output only a relatively low frequency, and a higher frequency is required. Needed to obtain a desired frequency by converting the output frequency of the direct digital synthesizer to a higher frequency.
FIG. 5 shows an example of a conventional frequency converter that converts the frequency of the low-frequency baseband signal into a high-frequency high-frequency signal. FIG. 5 is a block circuit diagram of an example of a conventional frequency conversion device. In FIG. 5, two baseband signals having a phase difference of 90 degrees from each other at the same frequency are output from the two-phase direct digital synthesizer 10 as the baseband signal generation means. The two-phase direct digital synthesizer 10 is provided with frequency data output from the frequency data generating means 11, and an output frequency is set according to this. The frequency data generation means 11 is configured to generate corresponding frequency data based on the hopping pattern code output from the frequency hopping pattern generation means 12 and sequentially output the data. Then, the two baseband signals of the two-phase direct digital synthesizer 10 are respectively supplied to the first balanced modulation means 14 and the second balanced modulation means 16 one by one. The high-frequency signal output from the high-frequency oscillator 18 is branched into two, one of which is supplied to the first balanced modulation means 14 as it is, and the other is shifted by 90 degrees by the 90-degree phase shifter 20. To the second balanced modulation means 16. Here, the high-frequency oscillator 18 and the 90-degree phase shifter 20 form local oscillation means 22 that outputs two local oscillation frequency signals having the same frequency and a phase difference of 90 degrees. Then, the outputs of the first balanced modulation means 14 and the second balanced modulation means 16 are added by an adding means 24 as a computing means, and a high frequency band signal is output.
[0003]
The operation of the frequency converter having such a configuration will be described. First, the baseband signals having two 90-degree phase differences of the two-phase direct digital synthesizer 10 are a · sinωt and a · cosωt,
If two local oscillation frequency signals having a phase difference of 90 degrees are b · cos ωct and b · sin ωct,
The output of the first balanced modulation means 14 is
ab · sinωt · cosωct,
The output of the second balanced modulation means 16 is
ab · cos ωt · sin ωct.
If the outputs of the first balanced modulation means 14 and the second balanced modulation means 16 are added, the calculation output is
ab · sin (ωc + ω) t.
Therefore, the baseband signal is frequency-converted into a high-frequency band signal that is higher by the frequency of the local oscillation frequency signal.
[0004]
By the way, the frequency of the baseband signal is sequentially switched in accordance with the hopping pattern code, but the frequency of the two-phase direct digital synthesizer 10 is relatively stable even when switched at high speed. Further, the local oscillation frequency signal is constant and stable without switching its frequency. Therefore, by using the frequency converter shown in FIG. 5, the frequency can be switched at high speed and a stable high frequency band signal can be obtained.
[0005]
[Problems to be solved by the invention]
As described above, the conventional frequency conversion device shown in FIG. 5 merely converts the baseband signal into a high-frequency band signal that is higher by the frequency of the local oscillation frequency signal. Therefore, as shown in FIG. 6, if the bandwidth in which the frequency of the baseband signal can be switched and set is w, the bandwidth of the frequency-converted high-frequency band signal is also w. For this reason, it is not possible to obtain a high-frequency band signal having a bandwidth wider than the bandwidth w of the two-phase direct digital synthesizer 10.
[0006]
By the way, since the two-phase direct digital synthesizer 10 is restricted by the sampling frequency and the calculation speed, it cannot output a signal having an arbitrarily high frequency. Therefore, the bandwidth in which the output frequency can be switched and set cannot be expanded sufficiently. On the other hand, recent frequency hopping spread spectrum communication systems require a high frequency output signal that has a wider output frequency bandwidth and can be switched stably at high speed. For this reason, the conventional frequency converter shown in FIG. 5 can be switched stably at high speed, but the bandwidth of the output frequency cannot be obtained sufficiently, and it is used in the recent frequency hopping spread spectrum communication system. It was impossible.
[0007]
The present invention has been made in view of the circumstances of the prior art as described above, and provides a frequency synthesizer device capable of obtaining an output band signal with a bandwidth twice that of the frequency signal. Objective.
[0008]
[Means for Solving the Problems]
In order to achieve such an object, a frequency synthesizer device according to the present invention includes a frequency signal generating unit that outputs two frequency signals having a phase difference of 90 degrees with each other at a frequency set according to frequency data, A second balanced modulation unit, a switching unit that switches according to the frequency data and supplies the two frequency signals one by one to the first and second balanced modulation units, respectively, and has a phase difference of 90 degrees from each other. An output band obtained by adding or subtracting the outputs of the local oscillation means for outputting the two local oscillation frequency signals to the first and second balanced modulation means one by one and the outputs of the first and second balanced modulation means one by one And an arithmetic means for outputting a signal.
[0009]
Further, frequency signal generating means for outputting two frequency signals having a phase difference of 90 degrees with each other at a frequency set according to the frequency data, and first and second frequency signals are provided one by one. Balanced modulation means, local oscillation means for outputting two local oscillation frequency signals having a phase difference of 90 degrees from each other, and switching between the two local oscillation frequency signals according to the frequency data, the first and second local oscillation frequency signals one by one It is also possible to comprise a switching means for supplying to each of the second balanced modulation means, and an arithmetic means for adding or subtracting the outputs of the first and second balanced modulation means to output an output band signal.
[0010]
Further, a frequency signal generating means for outputting two frequency signals having a phase difference of 90 degrees with each other at a frequency set according to the frequency data, and a first and a second that are provided with the two frequency signals one by one, respectively. Balanced oscillation means, local oscillation means for outputting two local oscillation frequency signals having a phase difference of 90 degrees to each other and supplying them to the first and second balanced modulation means one by one, and depending on the frequency data An arithmetic switching means for switching the addition and subtraction to calculate the outputs of the first and second balanced modulation means and output an output band signal may be provided.
[0011]
The frequency data conversion means is provided with the frequency data, and the frequency data conversion means provides the frequency setting data corresponding to the frequency data to the frequency signal generation means and the switching control data to the switching means. It can also be configured.
[0012]
The frequency data conversion means is provided with the frequency data, and the frequency data conversion means supplies the frequency setting data corresponding to the frequency data to the frequency signal generation means and the operation switching control data to the operation switching means. It can also be configured to give.
[0013]
The frequency data includes frequency setting data and switching control data, the frequency signal generating means outputs the frequency signal according to the frequency setting data, and the switching means is connected according to the switching control data. It may be configured to control switching.
[0014]
The frequency data includes frequency setting data and calculation switching control data, the frequency signal generation means outputs a frequency signal corresponding to the frequency setting data, and the calculation switching means responds to the calculation switching control data. You may comprise so that a calculation state may be switched.
[0015]
In addition, a frequency hopping pattern generation unit that sequentially generates hopping pattern codes may be provided, and the frequency data may be generated based on the hopping pattern codes.
[0016]
The frequency signal generation means may be configured to include a two-phase direct digital synthesizer.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block circuit diagram of a first embodiment of the frequency synthesizer device of the present invention. FIG. 2 is a diagram for explaining that the bandwidth of the output band signal can be obtained twice that of the frequency signal in the first embodiment. In FIG. 1, the same members as those in FIG.
[0018]
In FIG. 1, the difference from FIG. 5 is that two frequency signals having a phase difference of 90 degrees outputted from the two-phase direct digital synthesizer 10 are converted into the first balanced modulation one by one via the switching means 30. The frequency data output from the frequency data generating means 33 and the frequency data converting means 34 are supplied to the frequency data converting means 34 according to the frequency data. The frequency setting data is given to the two-phase direct digital synthesizer 10 and the switching control data corresponding to the frequency data is given to the switching means 30. Then, the output frequency of the two-phase direct digital synthesizer 10 is switched by the frequency setting data, and the connection state of the switching means 30 is switched by the switching control data, so that the two frequency signals are the first balanced modulation means 14 and the first balanced modulation means 14. Two balanced modulation means 16 are respectively provided. The frequency data generation unit 33 is configured to generate and output frequency data based on the hopping pattern code output from the frequency hopping pattern generation unit 32. More specifically, an example is described. Frequency data to be hopped is stored in advance in an appropriate memory (not shown) in the frequency data generation unit 33, and the corresponding frequency data is read out sequentially based on the hopping pattern code. It is configured to output. The frequency data generating means 33 may have any configuration as long as it can generate corresponding frequency data based on the hopping pattern code and sequentially output it.
[0019]
Here, the frequency data generated based on the hopping pattern code output from the frequency hopping pattern generation means 32 is set so that the frequency signal has a wider bandwidth than the bandwidth that can be output by the two-phase direct digital synthesizer 10. It is configured. Therefore, the frequency data conversion means 34 refers to a data table or the like stored in advance in an appropriate memory (not shown) and corresponds to the given frequency data, and the frequency within the bandwidth of the two-phase direct digital synthesizer 10. Frequency setting data for setting a signal and switching control data for switching control of the connection state of the switching means 30 for expanding the bandwidth as described later are calculated and output.
[0020]
In such a configuration, depending on one connection state of the switching means 30, the first balanced modulation means 14 includes
a · sinωt and b · cosωct are given,
The second balanced modulation means 16 includes
a · cos ωt and b · sin ωct are given, and in this control state, the adding means 24
An output band signal of ab · sin (ωc + ω) t is output.
Further, the first balanced modulation means 14 is connected to the other connection state in which the switching means 30 is switched.
a · cos ωt and b · cos ωct are given,
The second balanced modulation means 16 includes
a · sin ωt and b · sin ωct are given, and in this control state, the adding means 24
An output band signal of ab · cos (ωc−ω) t is output.
As a result, by appropriately switching the connection state of the switching means 30, as shown in FIG. 2, the frequency-converted output band signal is centered on the local oscillation frequency signal and the upper side of the frequency signal bandwidth w. Band and lower side band can be obtained together. Therefore, the bandwidth of the output band signal can be expanded to twice the bandwidth w of the frequency signal. Moreover, if the two-phase direct digital synthesizer 10 and the switching means 30 are switched at high speed according to the hopping pattern code, frequency hopping can be performed with wide bandwidth and high speed switching, which is suitable for a frequency hopping spread spectrum communication system. is there.
[0021]
The two-phase direct digital synthesizer 10 only needs to output a frequency signal having a relatively low frequency with respect to the output band signal, and does not include zero Hz even if the baseband signal has a bandwidth including zero Hz. It may be a bandwidth signal and is not limited to a specific frequency. Also, the output band signal only needs to be a relatively high frequency with respect to the frequency signal of the two-phase direct digital synthesizer 10, and is not specified to a specific high frequency. Further, the high frequency oscillator 18 of the local oscillating means 22 is also only given such a name because a practically high frequency is used, and the frequency of the local oscillation signal output from the local oscillating means 22 depends on the application. May be set appropriately. If the frequency signal of the two-phase direct digital synthesizer 10 has a bandwidth including zero Hz, the output band signal has a bandwidth w of a frequency signal in which the upper sideband and the lower sideband are continuous with the local oscillation frequency signal as the center. Twice as much bandwidth. Further, if the frequency signal has a bandwidth that does not include zero Hz, the output band signal is separated into the upper sideband and the lower sideband symmetrically about the local oscillation frequency signal, and the frequency signal bandwidth w and The same bandwidth is obtained, and the sum of the bandwidths of the upper sideband and the lower sideband is twice the bandwidth w of the frequency signal.
[0022]
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a block circuit diagram of a second embodiment of the frequency synthesizer device of the present invention. In FIG. 3, a relatively low frequency signal output from the one-phase direct digital synthesizer 40 is branched into two, one of which is supplied to the first balanced modulation means 14 as it is, and the other is a 90-degree phase shifter. At 42, the phase is shifted by 90 degrees and applied to the second balanced modulation means 16. Here, the one-phase direct digital synthesizer 40 and the 90-degree phase shifter 42 form frequency signal generation means 44 that outputs two frequency signals having the same frequency and a phase difference of 90 degrees. The output frequency of the one-phase direct digital synthesizer 40 is switched and set by frequency setting data as frequency data output from the frequency data generating means 45. This frequency data consists of frequency setting data and switching control data described later. Further, the high frequency signal output from the high frequency oscillator 48 is branched into two, one of which is advanced by 45 degrees by the +45 degree phase shifter 50 and the other is 45 by the −45 degree phase shifter 52. The phase is delayed by a degree. Thus, the +45 degree phase shifter 50 and the −45 degree phase shifter 52 output two local oscillation frequency signals having the same frequency and a phase difference of 90 degrees. The high frequency oscillator 48, the +45 degree phase shifter 50, and the −45 degree phase shifter 52 form a local oscillation means 54. Further, two local oscillation frequency signals of the local oscillating means 54 are supplied to the first balanced modulation means 14 and the second balanced modulation means 16 one by one via the switching means 56, respectively. The switching unit 56 is controlled to be switched by switching control data as frequency data output from the frequency data generating unit 45. Then, the outputs of the first balanced modulation means 14 and the second balanced modulation means 16 are subtracted by a subtracting means 58 as a computing means to output an output band signal.
[0023]
Here, in the second embodiment, frequency setting data and switching control data as frequency data are directly output from the frequency data generating means 45 and provided to the one-phase direct digital synthesizer 40 and the switching means 56. In the second embodiment, based on the hopping pattern code output from the frequency hopping pattern generation means 46, the frequency data generation means 45 is configured to directly generate frequency setting data and switching control data. Yes. More specifically, an example will be described. Frequency setting data and switching control data corresponding to a frequency to be hopped are stored in advance in an appropriate memory (not shown) in the frequency data generation unit 45, and the response is based on the hopping pattern code. The frequency setting data and switching control data to be read are read and sequentially output. The frequency data generating means 45 in the second embodiment can be any configuration as long as it can directly generate and sequentially output frequency setting data and switching control data as corresponding frequency data based on the hopping pattern code. It may be.
[0024]
Even in the frequency synthesizer device of the second embodiment having such a configuration, as in the first embodiment shown in FIG. 1, the frequency-converted output band signal has a frequency signal bandwidth w centered on the local oscillation frequency signal. The upper sideband and lower sideband are output and the bandwidth is doubled. Further, since the one-phase direct digital synthesizer 40 and the switching means 56 are directly controlled by the frequency setting data and the switching control data as the frequency data output from the frequency data generating means 45, compared with the first embodiment. A quick control can be performed as much as the arithmetic processing by the frequency data conversion means 34 is not required, and it is suitable for high-speed frequency hopping.
[0025]
Furthermore, a third embodiment of the present invention will be described with reference to FIG. FIG. 4 is a block circuit diagram of a third embodiment of the frequency synthesizer device of the present invention. In FIG. 4, a low frequency signal output from a low frequency oscillator 60 using a PLL circuit or the like is branched into two, one of which is a +45 degree phase shifter 62 and the phase thereof is advanced by 45 degrees. The other phase is supplied to the balanced modulation means 14 and the other phase is delayed by 45 degrees by the -45 degree phase shifter 64 and fed to the second balanced modulation means 16. The low frequency oscillator 60, the +45 degree phase shifter 62, and the −45 degree phase shifter 64 form a frequency signal generating means 66. The +45 degree phase shifter 62 and the −45 degree phase shifter 64 have the same frequency. Two frequency signals having a phase difference of 90 degrees are output. Here, the oscillation frequency of the low frequency oscillator 60 is switched and set by frequency setting data as frequency data output from the central processing means 68. Further, two local oscillation frequency signals having a phase difference of 90 degrees outputted from the local oscillation means 22 comprising the high frequency oscillator 18 and the 90 degree phase shifter 20 are supplied to the first balanced modulation means 14 and the first balanced modulation means 14 one by one. Two balanced modulation means 16 are provided. Then, the outputs of the first balanced modulation means 14 and the second balanced modulation means 16 are given to a calculation switching means 70 for switching between addition and subtraction, and an output band signal is output. The calculation switching means 70 is switched between addition and subtraction calculation states by calculation switching control data as frequency data output from the central calculation means 68.
[0026]
Note that the operation switching means 70 is not limited to the one whose operation is switched between addition and subtraction, and may be configured such that the addition means and the subtraction means are appropriately selected by the selection means. Further, the low frequency oscillator 60 may have any configuration as long as its oscillation frequency can be switched and controlled.
[0027]
Even in the frequency synthesizer device of the third embodiment having such a configuration, as in the first and second embodiments, the frequency-converted output band signal has a frequency signal bandwidth w centered on the local oscillation frequency signal. The upper sideband and lower sideband are output, and the bandwidth is wide.
[0028]
In the above-described embodiment, the frequency signal generation unit only needs to output two frequency signals having a phase difference of 90 degrees from each other, and is not limited to the structure of the above-described embodiment. The local oscillating means is not limited to the structure of the above embodiment as long as it can output two local oscillation frequency signals having a phase difference of 90 degrees. The frequency synthesizer device of the present invention is not limited to one that switches the output band signal at high speed, and even if the frequency signal generation means is not suitable for high-speed switching of the frequency signal, it is used according to its purpose. Of course you can. The frequency switching setting of the frequency signal of the two-phase direct digital synthesizer and the frequency signal generating means, and the switching control of the switching means or the arithmetic switching means are performed based on the hopping pattern code of the frequency hopping pattern generating means, The structure is not limited to that performed by the frequency data output from the calculation means, and any structure may be used as long as the switching is appropriately performed according to the frequency data for setting the output band signal.
[0029]
【The invention's effect】
As is apparent from the above description, since the frequency synthesizer device of the present invention is configured, the following special effects are achieved.
[0030]
In any of the frequency synthesizer devices according to claims 1 to 3, the bandwidth of the frequency-converted output band signal can be expanded to twice the bandwidth of the frequency signal.
[0031]
In the frequency synthesizer device according to claim 4 or 5, the frequency setting data for setting the frequency signal by appropriately converting the frequency data by the frequency data converting means and the switching control data for controlling the connection state of the switching means. Alternatively, since it is converted into calculation switching control data for controlling the calculation state of the calculation switching means, there are few restrictions on the frequency data.
[0032]
Further, in the frequency synthesizer device according to claim 6 or 7, the frequency signal setting and the connection state or calculation of the switching means are directly performed by frequency setting data as frequency data and switching control data or calculation switching control data. Since the calculation state of the switching means is controlled, the output band signal can be switched at high speed to the extent that there is no need to perform calculation processing.
[0033]
In the frequency synthesizer device according to claim 8, the frequency signal frequency is switched and set by the frequency data generated based on the hopping pattern code of the frequency hopping pattern generating means, and the switching means or the arithmetic switching means is provided. Since switching is performed as appropriate, the frequency of the output band signal can be easily switched.
[0034]
In the frequency synthesizer device according to the ninth aspect, since the frequency signal generating means includes the two-phase direct digital synthesizer, it is suitable for switching the frequency of the frequency signal at high speed. In particular, if the frequency data generated based on the hopping pattern code of the frequency hopping pattern generation means is switched at high speed by the frequency data, the frequency signal output from the two-phase direct digital synthesizer as the frequency signal generation means is changed to the hopping pattern code. Accordingly, the frequency of the output band signal is switched at a high speed and the bandwidth is widened, which is suitable for the frequency hopping spread spectrum communication system.
[Brief description of the drawings]
FIG. 1 is a block circuit diagram of a first embodiment of a frequency synthesizer device of the present invention.
FIG. 2 is a diagram for explaining that in the first embodiment of the frequency synthesizer device of the present invention, the bandwidth of the output band signal can be obtained twice the bandwidth of the frequency signal.
FIG. 3 is a block circuit diagram of a second embodiment of the frequency synthesizer device of the present invention.
FIG. 4 is a block circuit diagram of a third embodiment of the frequency synthesizer device of the present invention.
FIG. 5 is a block circuit diagram of an example of a conventional frequency conversion device.
FIG. 6 is a diagram for explaining that the bandwidth of a high-frequency band signal is the same as the bandwidth of a baseband signal in an example of a conventional frequency conversion device.
[Explanation of symbols]
10 2-phase direct digital synthesizer 11, 33, 45 Frequency data generation means 12, 32, 46 Frequency hopping pattern generation means 14 First balanced modulation means 16 Second balanced modulation means 22, 54 Local oscillation means 24 Addition means 30, 56 switching means 34 frequency data converting means 44, 66 frequency signal generating means 58 subtracting means 68 central processing means 70 arithmetic switching means

Claims (9)

Frequency signal generating means for outputting two frequency signals having a phase difference of 90 degrees with each other at a frequency set according to frequency data, first and second balanced modulation means, and switching according to the frequency data Switching means for supplying the two frequency signals to the first and second balanced modulation means one by one, and two local oscillation frequency signals having a phase difference of 90 degrees from each other to output the first frequency signal one by one. And a local oscillating means to be supplied to the second balanced modulation means, and an arithmetic means for adding or subtracting the outputs of the first and second balanced modulation means to output an output band signal. A frequency synthesizer device. Frequency signal generating means for outputting two frequency signals having a phase difference of 90 degrees at a frequency set according to frequency data, and first and second balanced modulations to which the two frequency signals are given one by one Means, local oscillation means for outputting two local oscillation frequency signals having a phase difference of 90 degrees from each other, and switching between the two local oscillation frequency signals according to the frequency data, the first and second local oscillation frequency signals one by one Switching frequency provided to each balanced modulation means, and arithmetic means for adding or subtracting the outputs of the first and second balanced modulation means to output an output band signal. Synthesizer device. Frequency signal generating means for outputting two frequency signals having a phase difference of 90 degrees with each other at a frequency set according to frequency data, and first and second balances to which the two frequency signals are respectively provided one by one Modulation means, local oscillation means for outputting two local oscillation frequency signals having a phase difference of 90 degrees to each other and supplying them to the first and second balanced modulation means one by one, and adding according to the frequency data A frequency synthesizer device comprising: an operation switching means for switching the subtraction to calculate the outputs of the first and second balanced modulation means and outputting an output band signal. 3. The frequency synthesizer device according to claim 1, further comprising frequency data conversion means to which the frequency data is given, and the frequency data conversion means gives frequency setting data corresponding to the frequency data to the frequency signal generation means. A frequency synthesizer device characterized in that switching control data is provided to the switching means. 4. The frequency synthesizer device according to claim 3, further comprising frequency data conversion means to which the frequency data is given, and the frequency data conversion means provides frequency setting data corresponding to the frequency data to the frequency signal generation means and operation switching. A frequency synthesizer device configured to provide control data to the calculation switching means. 3. The frequency synthesizer device according to claim 1, wherein the frequency data includes frequency setting data and switching control data, and the frequency signal generating means outputs the frequency signal according to the frequency setting data, and the switching means. Is a frequency synthesizer device configured to perform switching control of a connection state in accordance with the switching control data. 4. The frequency synthesizer device according to claim 3, wherein the frequency data includes frequency setting data and calculation switching control data, the frequency signal generation means outputs a frequency signal corresponding to the frequency setting data, and the calculation switching means A frequency synthesizer device configured to perform switching control of a calculation state in accordance with the calculation switching control data. 8. The frequency synthesizer device according to claim 1, further comprising frequency hopping pattern generation means for sequentially generating hopping pattern codes, wherein the frequency data is generated based on the hopping pattern codes. Synthesizer device. 9. The frequency synthesizer device according to claim 1, wherein the frequency signal generating means comprises a two-phase direct digital synthesizer.

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