JPH11243351A - Frequency synthesizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a frequency synthesizer suitable for fast switching which converts a low frequency signal into an output band signal of a higher frequency, and also expands the bandwidth by twice. SOLUTION: Two frequency signals with a 90 deg. phase difference which are outputted from a two-phase direct digital synthesizer 10 operating as a frequency signal generating means are given to 1st and 2nd balanced modulating means 14 and 16 one by one through a switching means 30. Also, two local oscillation frequency signals with a 90 deg. phase difference which are outputted from a local oscillating means 22 are given to the 1st and 2nd balanced modulating means 14 and 16 one by one. An output frequency of the synthesizer 10 is switched and set in accordance with a hopping pattern code outputted from a frequency hopping pattern code generating means 32 and also the means 30 is switched and controlled. An adding means 24 adds outputs of the means 14 and 16 and outputs an output band signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is capable of converting a frequency signal of a relatively low frequency into an output band signal of a higher frequency and expanding the bandwidth thereof, and furthermore, the output band signal of the expanded bandwidth is converted. The present invention relates to a frequency synthesizer device suitable for high-speed switching, and more particularly to a frequency synthesizer device suitable for use in a frequency hopping spread spectrum communication system.

[0002]

2. Description of the Related Art In a frequency hopping spread spectrum communication system, a frequency synthesizer capable of switching a frequency at high speed in accordance with various hopping patterns is required. 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 a frequency. 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. However, this direct digital synthesizer can output only a relatively low frequency, and when a higher frequency is required, this direct digital synthesizer can be used. It was necessary to convert the output frequency of the direct digital synthesizer to a higher frequency to obtain a desired frequency. FIG. 5 shows an example of a conventional frequency converter for frequency-converting the low-frequency baseband signal into a high-frequency high-frequency band signal. FIG. 5 is a block circuit diagram of an example of a conventional frequency conversion device. In FIG. 5, two baseband signals having the same frequency and a phase difference of 90 degrees are output from a two-phase direct digital synthesizer 10 as a baseband signal generating means. The two-phase direct digital synthesizer 10 is provided with the frequency data output from the frequency data generating means 11, and the output frequency is set accordingly. The frequency data generating means 11 is configured to generate corresponding frequency data based on a hopping pattern code output from the frequency hopping pattern generating means 12 and sequentially output the generated frequency 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 its phase 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 a local oscillation unit 22 that outputs two local oscillation frequency signals having the same frequency and a phase difference of 90 degrees from each other. Then, the outputs of the first balanced modulating means 14 and the second balanced modulating means 16 are added by an adding means 24 as a calculating means, and a high frequency band signal is output.

[0003] The operation of the frequency converter having the above configuration will be described. First, two baseband signals having a phase difference of 90 degrees of the two-phase direct digital synthesizer 10 are represented by a
• sinωt and a · cosωt, and if the local oscillation frequency signals having two 90 ° phase differences are b · cosωct and b · sinωct, the output of the first balanced modulation means 14 is ab · sinωt · cosωct. Yes, second
The output of the balanced modulation means 16 is ab · cosωt · si
nωct. Then, if the outputs of the first balanced modulating means 14 and the second balanced modulating means 16 are added, the calculated output is ab · sin (ωc + ω) t. Therefore, the baseband signal is frequency-converted into a high-frequency band signal higher by the frequency of the local oscillation frequency signal.

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 if the frequency is switched at high speed. In addition, the local oscillation frequency signal is constant and stable without being switched. Therefore, by using the frequency converter shown in FIG. 5, the frequency can be switched at a high speed and a stable high-frequency band signal can be obtained.

[0005]

As described above, the conventional frequency converter shown in FIG. 5 merely converts the frequency of a baseband signal into a high-frequency band signal higher by the frequency of a local oscillation frequency signal. Thus, 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 impossible to obtain a high-frequency band signal having a bandwidth wider than the bandwidth w of the two-phase direct digital synthesizer 10.

Incidentally, the two-phase direct digital synthesizer 10 cannot output a signal having an arbitrarily high frequency because it is limited by the sampling frequency and the operation speed. Therefore, the bandwidth in which the output frequency can be switched and set cannot be sufficiently increased. On the other hand, in recent frequency hopping spread spectrum communication systems, there is a need for a high frequency output signal that has a wider output frequency bandwidth and can be switched at high speed and stably. For this reason, in the conventional frequency converter shown in FIG. 5, switching can be performed at high speed and stably, but the bandwidth of the output frequency cannot be sufficiently obtained, so that it can be used in recent frequency hopping spread spectrum communication systems. It was impossible.

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 the bandwidth of a frequency signal. The purpose is to do.

[0008]

In order to achieve the above object, a frequency synthesizer according to the present invention outputs two frequency signals having a phase difference of 90 degrees with each other at a frequency set according to frequency data. Frequency signal generating means, first and second balanced modulation means, and switching means for switching the two frequency signals one by one to the first and second balanced modulation means by switching according to the frequency data, respectively. Local oscillation means for outputting two local oscillation frequency signals having a phase difference of 90 degrees to each other and applying the signals to the first and second balanced modulation means, respectively; Calculating means for adding or subtracting an output to output an output band signal.

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 a first and second frequency signal generating means for receiving the two frequency signals one by one. Second 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 one by one according to the frequency data to produce the first and second balanced modulation signals. It is also possible to comprise switching means to be applied to each means, and arithmetic means for adding or subtracting the outputs of the first and second balanced modulation means and outputting an output band signal.

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 signal to which the two frequency signals are given one by one And second balanced modulating means, local oscillating means for outputting two local oscillating frequency signals having a phase difference of 90 degrees from each other and providing the signals to the first and second balanced modulating means one by one, and the frequency data Operation switching means for switching between addition and subtraction in accordance with the above and calculating the outputs of the first and second balanced modulation means and outputting an output band signal.

And frequency data conversion means for receiving the frequency data. The frequency data conversion means provides frequency setting data corresponding to the frequency data to the frequency signal generation means and switches control data to the switching means. Can also be configured to be provided.

And frequency data conversion means to which the frequency data is provided, the frequency data conversion means providing frequency setting data corresponding to the frequency data to the frequency signal generation means and calculating switching control data to the calculation signal. It can also be configured to provide to the switching means.

Further, the frequency data includes frequency setting data and switching control data, the frequency signal generating means outputs the frequency signal in accordance with the frequency setting data, and the switching means responds to the switching control data. Alternatively, the connection state may be switched and controlled.

The frequency data comprises frequency setting data and operation switching control data, the frequency signal generating means outputs a frequency signal corresponding to the frequency setting data, and the operation switching means outputs the operation switching control data. May be configured to control the switching of the calculation state in accordance with.

The apparatus may further include frequency hopping pattern generation means for sequentially generating a hopping pattern code, and the frequency data may be generated based on the hopping pattern code.

The frequency signal generating means may include a two-phase direct digital synthesizer.

[0017]

FIG. 1 shows a first embodiment of the present invention.
This will be described with reference to FIG. 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 illustrating that the bandwidth of the output band signal is twice as large as the bandwidth of the frequency signal in the first embodiment. In FIG. 1, the same members as those in FIG. 5 are denoted by the same reference numerals, and redundant description will be omitted.

In FIG. 1, the difference from FIG. 5 is that two frequency signals output from the two-phase direct digital synthesizer 10 and having a phase difference of 90 degrees from each other are switched via the switching means 30 one by one. Are supplied to the balanced modulation means 14 and the second balanced modulation means 16 respectively, and the frequency data output from the frequency data generation means 33 is supplied to the frequency data conversion means 34. Is provided to the two-phase direct digital synthesizer 10 and the switching control data corresponding to the frequency data is provided 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.
The two frequency signals are provided to the first balanced modulation means 14 and the second balanced modulation means 16, respectively. This frequency data generating means 33 is a frequency hopping pattern generating means 3
2 is configured to generate and output frequency data based on the hopping pattern code output from 2. To describe one example more specifically, frequency data to be hopped is stored in advance in an appropriate memory (not shown) in the frequency data generation unit 33,
It is configured to read out corresponding frequency data based on the hopping pattern code and sequentially output the data.
The frequency data generating means 33 may have any configuration as long as it can generate the corresponding frequency data based on the hopping pattern code and sequentially output the frequency data.

Here, the frequency data generated based on the hopping pattern code output from the frequency hopping pattern generation means 32 sets a frequency signal with a bandwidth wider than the bandwidth that can be output by the two-phase direct digital synthesizer 10. It is configured to be. Therefore, the frequency data converter 34 refers to a data table or the like stored in advance in an appropriate memory (not shown),
Frequency setting data for setting a frequency signal within the bandwidth of the two-phase direct digital synthesizer 10 corresponding to the given frequency data, and the connection state of the switching means 30 for expanding the bandwidth as described later. And switching control data for switching control of the data.

In this configuration, the first balanced modulation means 14 has a · s
inωt and b · cosωct are given, and a · cosωt and b · sinωct are given to the second balanced modulation means 16. In such a control state, the addition means 24
An output band signal of ab · sin (ωc + ω) t is output. Further, the first balanced modulation means 14 is provided with a · cosωt by the other connection state in which the switching means 30 is switched.
And b · cosωct, and the second balanced modulation means 1
6 are given a · sin ωt and b · sin ωct. In this control state, the adder 24 outputs ab · sin ωt.
An output band signal of 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 becomes the center of the local oscillation frequency signal and the upper side of the bandwidth w of the frequency signal. Both band and lower side band are obtained. Therefore, the bandwidth of the output band signal can be expanded to twice the bandwidth w of the frequency signal. Moreover, a two-phase direct digital synthesizer 10
If the switching means 30 is switched at high speed in accordance with a hopping pattern code, frequency hopping can be performed with a wide bandwidth and high speed switching, which is suitable for a frequency hopping spread spectrum communication system.

The two-phase direct digital synthesizer 10 only needs to output a frequency signal having a frequency relatively lower than the output band signal. May not be limited to a specific frequency. Also, the output band signal need only be a frequency relatively higher than the frequency signal of the two-phase direct digital synthesizer 10, and is not specified to a specific high frequency or the like. Further, the high-frequency oscillator 18 of the local oscillation means 22
However, since a high frequency is used practically, such a name is merely used, and the frequency of the local oscillation signal output from the local oscillation means 22 may be appropriately set according to the application. If the frequency signal of the two-phase direct digital synthesizer 10 has a bandwidth including zero Hz, the output band signal is the bandwidth w of the frequency signal in which the upper side band and the lower side band are continuous with the local oscillation frequency signal as the center. Is obtained. If the frequency signal has a bandwidth that does not include zero Hz, the output band signal is symmetrically separated into an upper side band and a lower side band around the local oscillation frequency signal. The same bandwidth is obtained, and the sum of the bandwidths of the upper side band and the lower side band is twice the bandwidth w of the frequency signal.

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 according to the present invention. In FIG.
A relatively low frequency signal output from the one-phase direct digital synthesizer 40 is split into two,
One is supplied to the first balanced modulation means 14 as it is, and the other is phase-shifted by 90 degrees by the 90-degree phase shifter 42 and supplied to the second balanced modulation means 16. Here, a one-phase direct digital synthesizer 40 and a 90-degree phase shifter 4
2 forms a frequency signal generating means 44 for outputting two frequency signals having the same frequency and a phase difference of 90 degrees from each other. 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 unit 45. The frequency data includes frequency setting data and switching control data described later. A high-frequency signal output from the high-frequency oscillator 48 is branched into two, one of which is advanced by 45 degrees by a + 45-degree phase shifter 50 and the other is advanced by 45 degrees by a -45-degree phase shifter 52.
The phase is delayed by degrees. Therefore, 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 from each other. The high frequency oscillator 48 and the +45 degree phase shifter 5
A local oscillation means 54 is formed by the 0 and -45 degree phase shifters 52. Further, the two local oscillation frequency signals of the local oscillation means 54 are respectively supplied to the first balanced modulation means 14 and the second balanced modulation means 16 via the switching means 56 one by one. This switching means 56 is a frequency data generating means 45
The switching is controlled by the switching control data as frequency data output from the switch. Then, the first balanced modulation means 14
And the output of the second balanced modulation means 16 are subtracted by a subtraction means 58 as an operation means to output an output band signal.

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 supplied to the one-phase direct digital synthesizer 40 and the switching means 56. I have. In the second embodiment, the frequency data generator 45 is configured to directly generate frequency setting data and switching control data based on the hopping pattern code output from the frequency hopping pattern generator 46. I have. To describe one example more specifically, frequency setting data and switching control data corresponding to the frequency to be hopped are stored in advance in an appropriate memory (not shown) in the frequency data generating unit 45,
It is configured to read out corresponding frequency setting data and switching control data based on the hopping pattern code and sequentially output them. The frequency data generating means 45 in the second embodiment may have 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.

In the frequency synthesizer of the second embodiment having such a configuration, as in the first embodiment shown in FIG.
The frequency-converted output band signal is output as an upper side band and a lower side band having a bandwidth w of the frequency signal centered on the local oscillation frequency signal, 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 to the first embodiment. Fast control is possible as much as the calculation processing by the frequency data conversion means 34 is not required, and this is suitable for high-speed frequency hopping.

Further, 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 according to 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, and one of the signals is advanced by 45 degrees by a + 45-degree phase shifter 62 so that the first signal is advanced by 45 degrees. , And the other is delayed by 45 degrees by a -45 degree phase shifter 64 to be applied to the second balanced modulation means 16. And the low frequency oscillator 6
The 0, +45 degree phase shifter 62 and -45 degree phase shifter 64 form a frequency signal generating means 66, and the +45 degree phase shifter 62 and-
The 45-degree phase shifter 64 outputs two frequency signals having the same frequency and a phase difference of 90 degrees. 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. Also, two local oscillation frequency signals having a phase difference of 90 degrees from each other output from the local oscillation means 22 including the high-frequency oscillator 18 and the 90-degree phase shifter 20 are:
Each of them is provided to the first balanced modulation means 14 and the second balanced modulation means 16 one by one. Then, the outputs of the first balanced modulation means 14 and the second balanced modulation means 16 are provided to a calculation switching means 70 for performing a calculation by switching between addition and subtraction, and an output band signal is output. The operation switching means 70 switches the operation state of addition and subtraction by operation switching control data as frequency data output from the central processing means 68.

The operation switching means 70 is not limited to one in which the 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. good. The low frequency oscillator 60
May be any configuration as long as the oscillation frequency can be switched and controlled.

In the frequency synthesizer of the third embodiment having such a configuration, as in the first and second embodiments, the frequency-converted output band signal has a frequency band centered on the local oscillation frequency signal. The upper side band and the lower side band having the width w are output, and the bandwidth is wide.

In the above embodiment, the frequency signal generating means 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 embodiment. Also, the local oscillation means only needs to be able to output two local oscillation frequency signals having a phase difference of 90 degrees from each other, and is not limited to the structure of the above embodiment. The frequency synthesizer device of the present invention is not limited to the one that switches the output band signal at high speed, and is used in accordance with the purpose even if the frequency signal generation means is not suitable for high-speed switching of the frequency signal. Of course, you can do that. Further, the switching setting of the frequency 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 or the center. The structure is not limited to the one performed by the frequency data output from the calculating means, and may be any structure as long as the switching is appropriately controlled in accordance with the frequency data for setting the output band signal.

[0029]

As is apparent from the above description, since the frequency synthesizer of the present invention is constituted, the following special effects can be obtained.

In any of the frequency synthesizer devices according to the first to third aspects, the bandwidth of the frequency-converted output band signal can be expanded to twice the bandwidth of the frequency signal.

In the frequency synthesizer device according to the fourth or fifth aspect, the frequency data is appropriately converted by the frequency data conversion means to control the connection state between the frequency setting data for setting the frequency signal and the switching means. Since the data is converted into the switching control data or the operation switching control data for controlling the operation state of the operation switching means, there is little restriction on the frequency data.

In the frequency synthesizer according to the sixth or seventh aspect, the setting of the frequency signal and the connection of the switching means are directly performed by the frequency setting data and the switching control data or the arithmetic switching control data as the frequency data. Since the state or the operation state of the operation switching means is controlled, high-speed switching of the output band signal is possible as long as there is no need to perform the operation processing.

In the frequency synthesizer device according to the present invention, the frequency of the frequency signal is switched and set by the frequency data generated based on the hopping pattern code of the frequency hopping pattern generating unit, and the switching unit or the arithmetic unit is operated. Since the switching means is appropriately switched, the frequency of the output band signal can be easily switched.

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 signal output from the two-phase direct digital synthesizer as the frequency signal generating means is switched at high speed by the frequency data generated based on the hopping pattern code of the frequency hopping pattern generating means, Accordingly, the frequency of the output band signal is switched at a high speed and its bandwidth is expanded, so that it is suitable for use in a 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 according to the present invention.

FIG. 2 is a diagram illustrating that a bandwidth of an output band signal is twice as large as a bandwidth of a frequency signal in the first embodiment of the frequency synthesizer device of the present invention.

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 according to the present invention.

FIG. 5 is a block circuit diagram of an example of a conventional frequency conversion device.

FIG. 6 is a diagram illustrating 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 converter.

[Explanation of symbols]

 Reference Signs List 10 two-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 conversion means 44, 66 frequency signal generation means 58 subtraction means 68 central processing means 70 calculation switching means

Claims (9)

[Claims] 1. 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 frequency data, first and second balanced modulation means, Switching means for switching the two frequency signals one by one to the first and second balanced modulation means, respectively, and outputting two local oscillation frequency signals having a phase difference of 90 degrees from each other. A local oscillating means for giving the first and second balanced modulation means; and an arithmetic means for adding or subtracting the output of the first and second balanced modulation means to output an output band signal. A frequency synthesizer device comprising: 2. 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 frequency data; A second balanced modulating means, a local oscillating means for outputting two local oscillating frequency signals having a phase difference of 90 degrees from each other, and switching the two local oscillating frequency signals one by one according to the frequency data. Switching means for providing to the first and second balanced modulation means, respectively; and arithmetic means for adding or subtracting the output of the first and second balanced modulation means to output an output band signal. A frequency synthesizer device characterized by the above-mentioned. 3. 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 frequency data, and a first signal to which each of the two frequency signals is given one by one. And second balanced modulating means, local oscillating means for outputting two local oscillating frequency signals having a phase difference of 90 degrees from each other and providing the signals to the first and second balanced modulating means one by one, and the frequency data And a calculation switching means for calculating an output of the first and second balanced modulation means by switching between addition and subtraction in accordance with the calculation and outputting an output band signal. 4. The frequency synthesizer device according to claim 1, further comprising frequency data conversion means to which said frequency data is given, wherein said frequency data conversion means converts frequency setting data corresponding to said frequency data into said frequency signal. A frequency synthesizer device configured to supply the switching control data to the switching means and to the generating means. 5. The frequency synthesizer device according to claim 3, further comprising frequency data conversion means to which said frequency data is given, wherein said frequency data conversion means converts frequency setting data corresponding to said frequency data to said frequency signal generation means. And a calculation switching control data to the calculation switching means. 6. The frequency synthesizer according to claim 1, wherein said frequency data comprises frequency setting data and switching control data, and said frequency signal generating means outputs said frequency signal in accordance with said frequency setting data. The switching means is configured to switch and control the connection state in accordance with the switching control data. 7. The frequency synthesizer device according to claim 3, wherein said frequency data comprises frequency setting data and operation switching control data, and said frequency signal generating means outputs a frequency signal corresponding to said frequency setting data, A frequency synthesizer device, wherein the operation switching means is configured to switch the operation state according to the operation switching control data. 8. The frequency synthesizer according to claim 1, further comprising a frequency hopping pattern generating means for sequentially generating a hopping pattern code, wherein said frequency data is generated based on said hopping pattern code. A frequency synthesizer device characterized by the above-mentioned. 9. The frequency synthesizer device according to claim 1, wherein said frequency signal generating means includes a two-phase direct digital synthesizer.