JP2011127994A - Measuring apparatus and frequency changeover method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a measuring apparatus and a frequency changeover method capable of shortening a measuring time. <P>SOLUTION: A spectrum analyzer 100 includes a control voltage stabilization part 15 for stabilizing control voltages inputted by VCOs 12a, 12b and 12c which output signals of frequencies corresponding to the control voltages; and a sweep control part 20. The sweep control part 20 includes a voltage difference computation part 21 for computing a voltage difference corresponding to frequency changeover; a VCO changeover part 22 for changing over the VCOs; a waiting time determination part 23 for determining a waiting time; a control voltage output part 24 for outputting the control voltages to the control voltage stabilization part 15; a frequency information output part 25 for outputting frequency information (f) to a signal analysis part 18 after the elapse of the waiting time; and a data storage part 26 for previously storing waiting time characteristic data. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a measuring apparatus including a plurality of voltage controlled oscillators that generate local signals and a frequency switching method.

  Conventionally, a spectrum analyzer is known as a measuring apparatus having a configuration for generating a local signal. A spectrum analyzer is a device that displays a spectrum waveform indicating what level of signal is present at which frequency in a desired observation band, and generally has a basic configuration shown in FIG.

That is, the input signal _SIN is input to the mixer 52 of the frequency conversion unit 51, mixed with the local signal L from the local signal generator 53, and the frequency component of the difference or sum (hereinafter referred to as difference). Among them, a signal component M in a predetermined intermediate frequency band is extracted by the filter 54.

Here, assuming that the passing center frequency of the filter 54 is F _IF , the frequency of the local signal L is F _L, and mixing is performed with an upper heterodyne whose local frequency F _L is higher than the frequency F _IN of the analysis target signal to be converted to the intermediate frequency band. Assuming
_{F L} -F _IF = F _IN
The relationship holds.

Here, for _example, the F IF = 1 GHz, if swept local frequency _{F L} from 1.1GHz to 2 GHz, the frequency _{F IN} of the analyzed signal will vary from 100MHz to 1 GHz. That is, the filter 54, signal components from 100MHz to 1GHz of the input signal _{S IN} is to be extracted in chronological order of frequency of its original.

  Here, an example of a circuit that performs frequency conversion once is shown, but actually, frequency conversion processing (generally by a local signal of a fixed frequency) is performed a plurality of times in the frequency conversion unit 51, and Converting to a lower frequency band.

  The local signal generator 53 includes, for example, a PLL (phase locked loop) circuit, and is configured to output a local signal L having a frequency corresponding to externally applied data. The frequency sweep of the local signal L is performed. Is performed by sequentially updating the frequency data input from the sweep control unit 55.

  The sweep control unit 55 sweeps the frequency of the local signal L in a predetermined step according to a reference frequency (start frequency or center frequency), a sweep width (span), the number of acquired samples, and the like specified by an operation unit (not shown). The frequency information f indicating each frequency is given to the signal analysis unit 57 described later.

  On the other hand, the signal M output from the frequency converter 51 is sampled by the A / D converter 56 at a predetermined sampling period (a frequency more than twice the upper limit of the pass band of the filter 54), and obtained by the sampling. A digital signal sequence Dm is input to the signal analysis unit 57.

  The signal analysis unit 57 receives the digital signal sequence Dm obtained by the sweep and the frequency information f in association with each other, stores them in a memory (not shown), performs a designated band limiting process, etc., and performs a frequency within the observation band. A characteristic of the signal strength S (f), that is, a spectrum characteristic is obtained.

  The display unit 58 displays the spectrum characteristic waveform obtained by the signal analysis unit 57 on the screen as shown in FIG. 7, for example.

  By the way, in the spectrum analyzer having the basic configuration as described above, the required maximum observation band may be much wider than the sweep frequency width of one local signal generator. In recent years, in order to reduce costs, a measurement apparatus is configured using a voltage-controlled oscillator (VCO) that has a narrow sweep width but is inexpensive, instead of an expensive oscillator (YTO) having a wide sweep width and high signal purity. There is also a request to do so (for example, see Patent Document 1).

  In such a case, for example, as shown in FIG. 8, the required maximum observation band is divided into a plurality (in this case, three), and the local signals La˜ in the sweep frequency range respectively corresponding to the respective divided bands. The local signal generator 53 is composed of the voltage controlled oscillators 53a to 53c that respectively output Lc and the switches 53d and 53e that select these outputs.

  Further, a control signal stabilization circuit 59 is provided between the sweep control unit 55 and the local signal generator 53 in order to stabilize the control signal output from the sweep control unit 55.

  Then, when an observation band including two or more divided bands is designated, the sweep control unit 55 performs a sweep control of each of the voltage controlled oscillators 53a to 53c and a switching control of the switches 53d and 53e. It was like that.

Japanese Patent Laid-Open No. 08-201450

  However, in the configuration in which the control signal stabilization circuit 59 shown in FIG. 8 is provided, the time until the control signal is stabilized after the sweep control unit 55 outputs the control signal at the time of frequency switching (hereinafter referred to as “waiting time”). Since the signal to be analyzed is not stable until the time e.g.) elapses, analysis of the signal to be analyzed cannot be started in the signal analysis unit 57. The waiting time is determined by the frequency interval before and after switching and the time constant of the control signal stabilization circuit 59.

  Therefore, in the conventional measuring device, the maximum waiting time that maximizes the waiting time at the time of frequency switching is obtained in advance, the maximum waiting time is set as a fixed value, and the analysis is performed after the maximum waiting time elapses at each frequency switching. The analysis of the target signal was started.

  Therefore, the conventional measuring apparatus has a problem in that the maximum waiting time is fixed and the waiting time cannot be shortened, so that the measuring time for analyzing the analysis target signal cannot be shortened.

  The present invention has been made to solve the conventional problems, and it is an object of the present invention to provide a measuring apparatus and a frequency switching method that can shorten the measurement time.

  A measuring apparatus according to claim 1 of the present invention includes a plurality of voltage controlled oscillators (12a to 12c) that generate a signal having a frequency corresponding to an input voltage, and a frequency switching instruction unit (16) that instructs switching of the frequency. A voltage-controlled oscillator selection unit (22) that selects a voltage-controlled oscillator that generates a signal having a frequency instructed by the frequency switching instruction unit from among the plurality of voltage-controlled oscillators, and a voltage control selected by the voltage-controlled oscillator selection unit A voltage output unit (24) for outputting a voltage corresponding to the frequency in the oscillator, and a voltage stabilization unit for stabilizing the output voltage of the voltage output unit and outputting the voltage to the voltage controlled oscillator selected by the voltage controlled oscillator selecting unit (15), according to the first frequency when the frequency switching instruction unit instructs to switch from the first frequency to the second frequency. A voltage difference calculation unit (21) that calculates a voltage difference between the first voltage and the second voltage according to the second frequency, and the output voltage of the voltage output unit is stabilized from the first voltage. A data storage unit (26) for storing in advance waiting time voltage difference data representing a relationship between a waiting time indicating a time until switching to a voltage and a voltage difference between the first voltage and the second voltage; A waiting time determining unit (23) that determines the waiting time based on the voltage difference calculated by the voltage difference calculating unit and the waiting time voltage difference data stored in the data storage unit, and the voltage output unit includes the second voltage output unit. A frequency switching information output unit (25) that outputs information indicating that the frequency has been switched when the waiting time determined by the waiting time determination unit has elapsed since the voltage was output. .

  With this configuration, the measuring apparatus according to claim 1 of the present invention determines the waiting time according to the voltage difference calculated by the voltage difference calculation unit, so that the conventional apparatus using a preset fixed value waiting time is used. In addition, the waiting time at the time of frequency switching can be shortened. Therefore, the measuring apparatus according to claim 1 of the present invention can shorten the measurement time.

  Further, in the measuring apparatus according to claim 2 of the present invention, the voltage difference calculation unit includes a part of each frequency band of signals generated by the plurality of voltage controlled oscillators overlapping each other, and the first frequency band is overlapped with the first frequency band. When two frequencies are included, the first voltage difference between the voltage corresponding to the second frequency and the first voltage in the voltage controlled oscillator that generates a signal in one frequency band including the second frequency, and the other A voltage-controlled oscillator that generates a signal in a frequency band calculates a voltage corresponding to the second frequency and a second voltage difference between the first voltage, and the waiting time determination unit includes the first voltage difference. The waiting time is determined based on the smaller voltage difference of the second voltage differences and the waiting time voltage difference data.

  With this configuration, the measurement apparatus according to claim 2 of the present invention has a part of each frequency band of signals generated by a plurality of voltage controlled oscillators overlapping each other, and even when switching to a frequency included in the overlapping frequency band, The waiting time at the time of frequency switching can be shortened compared to the conventional case. Therefore, the measurement apparatus according to claim 2 of the present invention can shorten the measurement time.

  Furthermore, in the measuring apparatus according to claim 3 of the present invention, the voltage stabilizing unit (41) includes a plurality of series circuits (41a to 41c) in which a resistor (R2) and a capacitor (C) are connected in series, A switch (41d) for selecting one of the plurality of series circuits, and a time constant switching unit (42) for switching the time constant of the voltage stabilizing unit by switching the switch. It has a configuration.

  With this configuration, the measuring apparatus according to claim 3 of the present invention switches the time constant of the voltage stabilization unit, thereby stabilizing the input voltage input to the voltage controlled oscillator or improving the response speed of signal analysis or the like. Either of them can be prioritized.

  According to a fourth aspect of the present invention, there is provided a frequency switching method comprising: a plurality of voltage controlled oscillators for generating a signal having a frequency corresponding to an input voltage; a frequency switching instruction unit for instructing the frequency switching; and the plurality of voltage controlled oscillators. A voltage controlled oscillator selecting unit that selects a voltage controlled oscillator that generates a signal of a frequency instructed by the frequency switching instruction unit, and outputting a voltage corresponding to the frequency in the voltage controlled oscillator selected by the voltage controlled oscillator selecting unit And a voltage stabilization unit that stabilizes the output voltage of the voltage output unit and outputs the voltage to the voltage controlled oscillator selected by the voltage controlled oscillator selection unit. A frequency switching method for switching a frequency of a signal output from an oscillator, wherein the frequency switching instruction unit switches from a first frequency to a second frequency. A voltage difference calculating step (S12) for calculating a voltage difference between the first voltage corresponding to the first frequency and the second voltage corresponding to the second frequency when indicated, and the output voltage of the voltage output unit is Waiting time voltage difference data representing a relationship between a waiting time indicating a time until switching from the first voltage to the stabilized second voltage and a voltage difference between the first voltage and the second voltage. A waiting time determining step (S14) for determining the waiting time based on the waiting time voltage difference data and the voltage difference calculated in the voltage difference calculating step in advance, and the voltage output unit A frequency switching information output step (S16) that outputs information indicating that the frequency has been switched when the waiting time determined in the waiting time determination step has elapsed since the voltage was output. .

  With this configuration, the frequency switching method according to claim 4 of the present invention determines a waiting time according to the voltage difference calculated in the voltage difference calculating step, and thus a conventional method using a fixed waiting time set in advance. As a result, the waiting time during frequency switching can be shortened. Therefore, the frequency switching method according to claim 4 of the present invention can shorten the measurement time.

  Further, in the frequency switching method according to claim 5 of the present invention, in the voltage difference calculating step, a part of each frequency band of the signals generated by the plurality of voltage controlled oscillators overlaps each other, and the frequency band is overlapped with the frequency band. When the second frequency is included, the first voltage difference between the voltage corresponding to the second frequency and the first voltage in the voltage controlled oscillator that generates a signal in one frequency band including the second frequency, and the other And calculating a second voltage difference between the voltage according to the second frequency and the first voltage in the voltage controlled oscillator that generates a signal in the frequency band of the first frequency difference, and in the waiting time determining step, the first voltage difference and the second voltage difference The waiting time is determined based on the smaller voltage difference of the second voltage differences and the waiting time voltage difference data.

  With this configuration, the frequency switching method according to claim 5 of the present invention can be used even when a part of each frequency band of the signal generated by the plurality of voltage controlled oscillators overlaps and switches to a frequency included in the overlapping frequency band. The waiting time at the time of frequency switching can be shortened compared to the conventional case. Therefore, the frequency switching method according to claim 5 of the present invention can shorten the measurement time.

  Furthermore, in the frequency switching method according to claim 6 of the present invention, the voltage stabilizing unit selects a plurality of series circuits in which resistors and capacitors are connected in series, and one of the plurality of series circuits. And a switch including a time constant switching step of switching the time constant of the voltage stabilizing unit by switching the switch.

  With this configuration, in the frequency switching method according to claim 6 of the present invention, the input voltage input to the voltage controlled oscillator is stabilized or the response speed of the signal analysis is improved by switching the time constant of the voltage stabilizing unit. Priority can be given to either of the conversion.

  The present invention can provide a measuring apparatus and a frequency switching method having an effect that the measurement time can be shortened.

It is a block diagram which shows the structure of the spectrum analyzer which is one Embodiment of the measuring apparatus which concerns on this invention. In the spectrum analyzer which is one embodiment of the measuring device according to the present invention, it is an example of control voltage characteristic data indicating the relationship between the frequency of the signal output from the VCO and the VCO control voltage. In the spectrum analyzer which is one Embodiment of the measuring apparatus which concerns on this invention, it is explanatory drawing of the calculation method of the waiting time by a waiting time determination part. It is a flowchart of the frequency switching operation | movement in the spectrum analyzer which is one Embodiment of the measuring apparatus which concerns on this invention. It is a figure which shows the other structural example of a control voltage stabilization part in the spectrum analyzer which is one Embodiment of the measuring apparatus which concerns on this invention. It is a block diagram which shows the structure of the conventional spectrum analyzer. It is a figure which shows the example of a waveform of the spectrum characteristic displayed in the conventional spectrum analyzer. In the conventional spectrum analyzer, it is a block diagram of the local signal generator provided with the several voltage control oscillator.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. An example in which the measurement apparatus of the present invention is applied to a spectrum analyzer will be described.

  First, the configuration of a spectrum analyzer according to an embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the spectrum analyzer 100 according to the present embodiment includes a frequency conversion unit 10, a control voltage stabilization unit 15, an operation unit 16, an A / D converter 17, a signal analysis unit 18, a display unit 19, and a sweep control. The unit 20 is provided.

  The frequency conversion unit 10 includes an attenuator (ATT) 11, a local signal generator 12, a mixer 13, and a filter 14.

ATT11 the attenuation a variable attenuator attenuates the level of the input signal S _IN to a predetermined value, and outputs it to the mixer 13.

  The local signal generator 12 includes three voltage controlled oscillators (VCO) 12a, 12b and 12c, and switches 12d and 12e for selecting one of them, and generates a local signal L and outputs it to the mixer 13. It is supposed to be. In the present embodiment, the local signal generator 12 includes three VCOs. However, the present invention is not limited to this, and it is only necessary to include a plurality of VCOs.

  The VCOs 12a, 12b, and 12c are configured to output signals La, Lb, and Lc having frequencies corresponding to the VCO control voltage by inputting the VCO control voltage, respectively. Specifically, for example, as shown in FIG. 2, the VCO 12a is a frequency band from 1 GHz to 1.4 GHz, and the VCO 12b is a frequency band from 1.3 GHz to 1.7 GHz according to a VCO control voltage from 2 V to 20 V. The VCO 12c outputs a signal in a frequency band from 1.6 GHz to 2 GHz. Hereinafter, data indicating the relationship between the frequency and the VCO control voltage as illustrated in FIG. 2 is referred to as “control voltage characteristic data”. The VCOs 12a, 12b and 12c constitute a plurality of voltage controlled oscillators according to the present invention.

  Here, the frequency bands of the VCO 12a and the VCO 12b overlap each other in the frequency band from 1.3 GHz to 1.4 GHz. Further, the frequency bands of the VCO 12b and the VCO 12c overlap each other in a frequency band from 1.6 GHz to 1.7 GHz. Accordingly, there are two VCO control voltages in the overlapping frequency regions. In FIG. 2, each characteristic of the VCOs 12a, 12b, and 12c is represented by a straight line. However, the present invention is not limited to this.

  The mixer 13 mixes the output signal of the ATT 11 and the local signal L, and outputs the mixed signal to the filter 14.

Filter 14 passes the signal component M of a predetermined frequency among of the input signal S _IN, and is adapted to output to the A / D converter 17.

  The control voltage stabilizing unit 15 includes a circuit including resistors R1 and R2 and a capacitor C. The control voltage stabilizing unit 15 stabilizes the VCO control voltage output from the sweep control unit 20 and outputs the stabilized VCO control voltage to the local signal generator 12. Here, the control voltage stabilizing unit 15 constitutes a voltage stabilizing unit according to the present invention.

  The operation unit 16 includes, for example, operation buttons. The measurement conditions are set by the operator operating the operation unit 16. Specifically, when the measurer operates the operation unit 16, setting of the attenuation amount of the ATT 11, setting and switching of the frequency of the local signal L, setting of analysis conditions in the signal analysis unit 18, and the like are performed. ing. Here, the operation unit 16 constitutes a frequency switching instruction unit according to the present invention.

  Note that the measurement conditions may be set with a configuration that replaces the operation unit 16. Specifically, in a spectrum analyzer having a function called a list operation mode, a remote control function, and the like, measurement conditions can be set by, for example, a CPU and a program instead of the operation unit 16. Here, the list operation mode refers to a mode in which a measurement operation is continuously performed according to a list including a plurality of measurement items preset by the measurer.

  The A / D converter 17 inputs an analog signal component passed through the filter 14, samples it at a predetermined sampling period, and outputs a digital signal sequence Dm to the signal analysis unit 18.

  The signal analysis unit 18 associates the digital signal sequence Dm obtained by the sweep with the frequency information f output by the sweep control unit 20 and stores it in a memory (not shown), and performs a specified band limiting process or the like. A characteristic of frequency vs. signal intensity S (f) in the observation band, that is, a spectrum characteristic is obtained.

  The display unit 19 is composed of, for example, a liquid crystal display, and displays the waveform of the spectrum characteristic obtained by the signal analysis unit 18.

  The sweep control unit 20 includes, for example, a CPU, a ROM, a RAM, and the like, and includes a voltage difference calculation unit 21, a VCO switching unit 22, a waiting time determination unit 23, a control voltage output unit 24, a frequency information output unit 25, and a data storage unit 26. It has.

  Based on the control voltage characteristic data illustrated in FIG. 2, the voltage difference calculation unit 21 receives the first voltage corresponding to the first frequency and the first voltage when the operation unit 16 instructs to switch from the first frequency to the second frequency. A voltage difference ΔV from the second voltage corresponding to the two frequencies is calculated. Hereinafter, a specific description will be given based on FIG. The control voltage characteristic data is stored in advance in the data storage unit 26.

  In FIG. 2, a description will be given based on the case where the VCO 12a receives the VCO control voltage Va and outputs a signal of frequency Fa (point A).

  First, it is assumed that the operation unit 16 instructs to switch from the frequency Fa to the frequency Fb. In this case, since the frequency Fb corresponds to the point B on the characteristic line of the VCO 12a, the voltage difference calculation unit 21 calculates the voltage difference ΔVb between the points A and B on the characteristic line of the VCO 12a.

  Next, it is assumed that the operation unit 16 instructs to switch from the frequency Fa to the frequency Fc. In this case, the frequency Fc exists in the overlapping frequency band of the VCO 12a and the VCO 12b. That is, the frequency Fc corresponds to the point C1 on the characteristic line of the VCO 12a and the point C2 on the characteristic line of the VCO 12b. In this case, the voltage difference calculating unit 21 calculates the voltage difference ΔVc1 between the points A and C1 on the characteristic line of the VCO 12a and the voltage difference between the point A on the characteristic line of the VCO 12a and the point C2 on the characteristic line of the VCO 12b. ΔVc2 is calculated, and the smaller voltage difference (ΔVc2 in FIG. 2) is adopted. When both are at the same voltage, it is preferable to employ the voltage difference of the currently selected VCO.

  Next, it is assumed that the operation unit 16 instructs to switch from the frequency Fa to the frequency Fd. In this case, since the frequency Fd corresponds to the point D on the characteristic line of the VCO 12b, the voltage difference calculation unit 21 calculates the voltage difference ΔVd between the point A on the characteristic line of the VCO 12a and the point D on the characteristic line of the VCO 12b. To do.

  Next, it is assumed that the operation unit 16 instructs to switch from the frequency Fa to the frequency Fe. In this case, since the frequency Fe corresponds to the point E on the characteristic line of the VCO 12c (the same voltage as the point A), the voltage difference calculation unit 21 calculates the point A on the characteristic line of the VCO 12a and the point E on the characteristic line of the VCO 12c. A voltage difference ΔVe (= 0) is calculated.

  As described above, the voltage difference calculation unit 21 calculates the voltage difference ΔV according to the frequency switching when the operation unit 16 instructs to switch the frequency of the local signal L. In addition, the voltage difference calculation unit 21 outputs the calculated voltage difference ΔV to the waiting time determination unit 23 as voltage difference information.

  Further, the voltage difference calculation unit 21 outputs VCO switching instruction information for switching the VCO to the VCO switching unit 22 after calculating the voltage difference ΔV. For example, when the operation unit 16 instructs to switch from the frequency Fa to the frequency Fc, the voltage difference calculation unit 21 outputs VCO switching instruction information for switching from the VCO 12 a to the VCO 12 b to the VCO switching unit 22. When there is no need to switch the VCO, the voltage difference calculation unit 21 may not output the VCO switching instruction information to the VCO switching unit 22.

  The VCO switching unit 22 receives the VCO switching instruction information from the voltage difference calculation unit 21, operates the switches 12d and 12e based on the VCO switching instruction information, and selects any one of the VCOs 12a, 12b, and 12c. It is supposed to be. The VCO switching unit 22 constitutes a voltage controlled oscillator selection unit according to the present invention.

  The waiting time determination unit 23 receives the voltage difference signal from the voltage difference calculation unit 21 and determines the waiting time based on the voltage difference signal. Here, the waiting time refers to the time until the output voltage of the control voltage output unit 24 switches from the first voltage to the stabilized second voltage. The degree of stabilization of the second voltage can be determined according to the level fluctuation. Hereinafter, based on FIG. 3, the function of the waiting time determination part 23 is demonstrated concretely.

  As shown in FIG. 3A, it is assumed that there is an instruction to switch from the frequency F0 to the frequency F1 by the operation unit 16. In this case, the voltage difference calculation unit 21 calculates the voltage difference ΔV1 from the VCO control voltages V0 and V1 corresponding to the frequencies F0 and F1, respectively, based on the control voltage characteristics of the VCO 12a. Then, the voltage difference calculation unit 21 sends voltage difference information indicating the voltage difference ΔV <b> 1 to the waiting time determination unit 23.

  The waiting time determination unit 23 receives the voltage difference information indicating the received voltage difference ΔV1 and data 31 indicating the relationship between the voltage difference ΔV and the waiting time T shown in FIG. 3B (hereinafter referred to as “waiting time characteristic data 31”). The waiting time is determined based on the above and the waiting time T1 is obtained. Here, as shown in FIG. 3B, the waiting time characteristic data 31 indicates that the waiting time T decreases as the voltage difference ΔV decreases. The waiting time characteristic data 31 is stored in the data storage unit 26 in advance.

  Similarly, the waiting time determination unit 23 obtains the waiting time T2 when the voltage difference information indicating the voltage difference ΔV2 when the frequency F0 is switched to the frequency F2 in FIG. 3A is received. Similarly, the waiting time determination unit 23 obtains a waiting time T3 when voltage difference information indicating the voltage difference ΔV3 when the frequency F0 is switched to the frequency F3 is received.

  As described above, the waiting time determination unit 23 determines the waiting time based on the voltage difference information and the waiting time characteristic data 31, and outputs the determined waiting time to the frequency information output unit 25 as the waiting time information. It has become.

  The waiting time determination unit 23 outputs control voltage instruction information indicating the VCO control voltage corresponding to the frequency after switching to the control voltage output unit 24.

  In place of the waiting time characteristic data 31 shown in FIG. 3B, the waiting time characteristic data obtained by adding a predetermined time margin to the waiting time characteristic data 31 as shown by a broken line in FIG. 32, the waiting time determining unit 23 may determine the waiting time corresponding to the voltage difference ΔV. Alternatively, the function data indicating the waiting time characteristic data 31 may be stored in the data storage unit 26, and the waiting time determination unit 23 may calculate the waiting time corresponding to the voltage difference ΔV using the function. In FIG. 3B, the waiting time characteristic data 31 and 32 are shown by straight lines, but the present invention is not limited to this.

  The control voltage output unit 24 receives control voltage instruction information from the waiting time determination unit 23 and outputs a VCO control voltage based on the control voltage instruction information to the control voltage stabilization unit 15. In addition, the control voltage output unit 24 outputs control voltage output time information indicating the time when the VCO control voltage is output to the control voltage stabilization unit 15 to the frequency information output unit 25. The control voltage output unit 24 constitutes a voltage output unit according to the present invention.

  The frequency information output unit 25 receives the waiting time information from the waiting time determination unit 23 and receives the control voltage output time information from the control voltage output unit 24. Further, the frequency information output unit 25 outputs frequency information f indicating the frequency of the local signal L to the signal analysis unit 18 when the waiting time elapses from the control voltage output time. As a result, the signal analysis unit 18 can know to which frequency the frequency of the local signal L has been switched. The frequency information output unit 25 constitutes a frequency switching information output unit according to the present invention.

  The frequency information output unit 25 outputs, for example, the frequency information f to the signal analysis unit 18 before the waiting time elapses, and outputs a signal indicating the start of measurement to the signal analysis unit 18 after the waiting time elapses. Thus, the signal analysis unit 18 may be configured to start signal analysis based on the frequency information f.

  The data storage unit 26 stores the control voltage characteristic data illustrated in FIG. 2 and the waiting time characteristic data 31 illustrated in FIG. 3B in advance. The control voltage characteristic data and the waiting time characteristic data 31 are data acquired in advance by experiments or the like.

  Next, the operation of the spectrum analyzer 100 in the present embodiment will be described with reference to FIGS. In the following description, a frequency switching operation for switching the frequency of the local signal L from the frequency Fa to the desired frequency Fx in the spectrum analyzer 100 will be described. Further, it is assumed that the voltage difference calculation unit 21 reads the control voltage characteristic data and the waiting time determination unit 23 reads the waiting time characteristic data 31 from the data storage unit 26, respectively.

  First, the measurer operates the operation unit 16 to switch the frequency, and inputs a desired frequency Fx (step S11). As a result, the voltage difference calculation unit 21 acquires information on the frequency Fx.

  Based on the control voltage characteristic data read from the data storage unit 26, the voltage difference calculation unit 21 is a voltage between the VCO control voltage Va corresponding to the current frequency Fa of the local signal L and the VCO control voltage corresponding to the frequency Fx. The difference ΔV is calculated (step S12). The voltage difference information indicating the voltage difference ΔV is sent from the voltage difference calculation unit 21 to the waiting time determination unit 23. Step S12 constitutes a voltage difference calculation step according to the present invention.

  Further, the voltage difference calculation unit 21 outputs VCO switching instruction information for switching the VCO to the VCO switching unit 22. The VCO switching unit 22 operates the switches 12d and 12e based on the VCO switching instruction information to switch the VCO (step S13).

  The waiting time determination unit 23 determines the waiting time T based on the voltage difference information output from the voltage difference calculation unit 21 in step S12 and the waiting time characteristic data 31 read from the data storage unit 26 (step S14). Step S14 constitutes a waiting time determining step according to the present invention.

  Then, the waiting time determination unit 23 outputs control voltage instruction information indicating the VCO control voltage corresponding to the frequency after switching to the control voltage output unit 24. The waiting time determination unit 23 outputs the determined waiting time T to the frequency information output unit 25 as waiting time information. Note that the order of step S14 for determining the waiting time and step S13 for switching the VCO may be interchanged.

  The control voltage output unit 24 receives the control voltage instruction information from the waiting time determination unit 23, and outputs the VCO control voltage based on the control voltage instruction information to the control voltage stabilization unit 15 (step S15). As a result, the control voltage stabilization unit 15 stabilizes the VCO control voltage and outputs it to the local signal generator 12. Further, the control voltage output unit 24 outputs the control voltage output time information to the frequency information output unit 25.

  The frequency information output unit 25 receives the waiting time information from the waiting time determination unit 23 and also receives the control voltage output time information from the control voltage output unit 24. Then, when the waiting time elapses from the control voltage output time, the frequency information output unit 25 outputs the frequency information f indicating the frequency of the local signal L to the signal analysis unit 18 (step S16). As a result, the signal analysis unit 18 can start signal analysis based on the frequency information f. Step S16 constitutes a frequency switching information output step according to the present invention.

  Next, the effect of shortening the waiting time during frequency switching obtained by the spectrum analyzer 100 will be described.

  In a general spectrum analyzer, the minimum waiting time determined by the combination of the minimum voltage difference ΔV corresponding to the switching frequency interval of the minimum step and the minimum value of the general time constant of the control voltage stabilizing unit 15 is about 1 ms. It is. On the other hand, for example, in the VCO 12a shown in FIG. 2, the switching frequency interval of the maximum step corresponding to the case where the VCO control voltage is changed from 2V to 20V is 0.4 GHz. The maximum waiting time determined by the combination of the maximum voltage difference ΔV corresponding to the switching frequency interval of the maximum step and the maximum value of the general time constant of the control voltage stabilizing unit 15 is about 25 ms. Therefore, the waiting time ranges from about 1 ms to about 25 ms. The switching time of the switches 12d and 12e for switching the VCO is neglected because it is about 10 μs.

  In the conventional spectrum analyzer, as described in the [Problems to be solved by the invention] column, the maximum waiting time is fixed and used, so the waiting time is about 25 ms.

  On the other hand, the spectrum analyzer 100 according to the present embodiment is configured to determine the waiting time according to the voltage difference ΔV calculated by the voltage difference calculating unit 21, and therefore the waiting time is always about 25 ms or less. Therefore, since the spectrum analyzer 100 can shorten the waiting time as compared with the conventional spectrum analyzer, the measurement time can be shortened. In particular, in the spectrum analyzer 100, the effect of shortening the measurement time increases as the number of frequency switching increases as in the case of performing a series of measurements continuously.

  As described above, according to the spectrum analyzer 100 of the present embodiment, the waiting time determination unit 23 is configured to determine the waiting time according to the voltage difference ΔV calculated by the voltage difference calculation unit 21, and thus obtained in advance. The waiting time at the time of frequency switching can be shortened as compared with the conventional one in which the maximum waiting time is a fixed value. Therefore, the spectrum analyzer 100 according to the present embodiment can reduce the measurement time.

  Further, according to the spectrum analyzer 100 in the present embodiment, even when a part of each frequency band of the signals generated by the plurality of VCOs 12a, 12b, and 12c overlaps each other and is switched to a frequency included in the overlapping frequency band, The waiting time at the time of switching can be shortened compared to the conventional case. Therefore, the spectrum analyzer 100 according to the present embodiment can reduce the measurement time.

  In the above-described embodiment, the spectrum analyzer 100 has been described as an example. However, the present invention is not limited to this, and the same is applied to a measurement apparatus including a plurality of voltage-controlled oscillators that generate local signals. An effect is obtained.

  Moreover, although the above-mentioned control voltage stabilization part 15 gave and demonstrated the example comprised with the circuit (refer FIG. 1) each including resistance R1, R2 and the capacitor | condenser C, it may also be set as the structure described below. it can.

  In the spectrum analyzer 100, the stability of the VCO control voltage is determined by the time constant of the control voltage stabilization unit 15. As the time constant of the control voltage stabilization unit 15 increases, the VCO control voltage can be stabilized, and a VCO control voltage signal with less noise can be obtained. On the other hand, as the time constant of the control voltage stabilizing unit 15 is smaller, the response speed of signal processing can be improved and a sharp spectrum characteristic waveform can be obtained. That is, there is a trade-off between stabilizing the VCO control voltage and improving the response speed. Therefore, a control voltage stabilization unit 41 as shown in FIG.

  The control voltage stabilization unit 41 shown in FIG. 5 includes a resistor R1, three RC series circuits 41a to 41c in which a resistor R2 and a capacitor C are connected in series, and a switch 41d that switches the RC series circuits 41a to 41c. I have. Each of the three RC series circuits 41a to 41c has a resistance value of each resistor R2 and a capacitance of each capacitor C as shown in the figure, for example, and has different time constants. The switch 41d is configured to switch the RC series circuits 41a to 41c according to a control signal from the time constant switching unit 42. The time constant can be set together with the input of the frequency Fx, for example, in step S11 shown in FIG.

  With the above-described configuration, the spectrum analyzer 100 can switch the time constant of the control voltage stabilization unit 41. Therefore, in signal analysis or the like, priority is given to either stabilization of the VCO control voltage or improvement of response speed. be able to.

  As described above, the measuring apparatus and the frequency switching method according to the present invention have an effect that the measurement time can be shortened, and the measuring apparatus and the frequency including a plurality of voltage-controlled oscillators that generate local signals. This is useful as a switching method.

10 Frequency converter 11 ATT
12 local signal generator 12a-12c VCO (voltage controlled oscillator)
12d, 12e Switch 13 Mixer 14 Filter 15, 41 Control voltage stabilization unit (voltage stabilization unit)
16 Operation part (frequency switching instruction part)
17 A / D converter 18 Signal analysis unit 19 Display unit 20 Sweep control unit 21 Voltage difference calculation unit 22 VCO switching unit (voltage controlled oscillator selection unit)
23 Waiting time determining unit 24 Control voltage output unit (voltage output unit)
25 Frequency information output part (frequency switching information output part)
26 Data storage unit 31, 32 Latency characteristic data 41a to 41c RC series circuit 41d Switch 42 Time constant switching unit 100 Spectrum analyzer (measuring device)

Claims (6)

A plurality of voltage controlled oscillators (12a to 12c) for generating a signal of a frequency according to an input voltage; a frequency switching instruction unit (16) for instructing switching of the frequency; and the frequency switching of the plurality of voltage controlled oscillators A voltage-controlled oscillator selection unit (22) that selects a voltage-controlled oscillator that generates a signal having a frequency instructed by the instruction unit; and a voltage that outputs a voltage corresponding to the frequency in the voltage-controlled oscillator selected by the voltage-controlled oscillator selection unit A measurement apparatus comprising: an output unit (24); and a voltage stabilization unit (15) that stabilizes an output voltage of the voltage output unit and outputs the voltage to a voltage controlled oscillator selected by the voltage controlled oscillator selection unit. And
A voltage difference for calculating a voltage difference between the first voltage corresponding to the first frequency and the second voltage corresponding to the second frequency when the frequency switching instruction unit instructs to switch from the first frequency to the second frequency. A calculation unit (21);
A relationship between a waiting time indicating a time until the output voltage of the voltage output unit switches from the first voltage to the stabilized second voltage, and a voltage difference between the first voltage and the second voltage. A data storage unit (26) for previously storing the waiting time voltage difference data represented;
A waiting time determining unit (23) for determining the waiting time based on the voltage difference calculated by the voltage difference calculating unit and the waiting time voltage difference data stored in the data storage unit;
A frequency switching information output unit (25) that outputs information indicating that the frequency has been switched when the waiting time determined by the waiting time determination unit has elapsed since the voltage output unit output the second voltage; A measuring device characterized by comprising. The voltage difference calculation unit includes the second frequency when a part of each frequency band of signals generated by the plurality of voltage controlled oscillators overlaps and the second frequency is included in the overlapping frequency band. The first voltage difference between the voltage according to the second frequency and the first voltage in the voltage controlled oscillator that generates a signal in one frequency band, and the second voltage in the voltage controlled oscillator that generates a signal in the other frequency band. Calculating a voltage according to frequency and a second voltage difference between the first voltage,
The waiting time determination unit is configured to determine the waiting time based on a smaller voltage difference of the first voltage difference and the second voltage difference and the waiting time voltage difference data. The measuring apparatus according to claim 1. The voltage stabilizing unit (41) includes a plurality of series circuits (41a to 41c) in which a resistor (R2) and a capacitor (C) are connected in series, and a switch that selects one of the plurality of series circuits. (41d), and
The measuring apparatus according to claim 1 or 2, further comprising a time constant switching unit (42) that switches a time constant of the voltage stabilizing unit by switching the switch. A plurality of voltage controlled oscillators for generating a signal having a frequency according to an input voltage, a frequency switching instruction unit for instructing switching of the frequency, and a signal of a frequency instructed by the frequency switching instruction unit among the plurality of voltage controlled oscillators A voltage controlled oscillator selecting unit that selects a voltage controlled oscillator that generates the voltage, a voltage output unit that outputs a voltage according to the frequency in the voltage controlled oscillator selected by the voltage controlled oscillator selecting unit, and an output voltage of the voltage output unit And a voltage stabilizing unit that outputs to the voltage controlled oscillator selected by the voltage controlled oscillator selecting unit, and a frequency switching method for switching frequencies of signals output by the plurality of voltage controlled oscillators There,
A voltage difference for calculating a voltage difference between the first voltage corresponding to the first frequency and the second voltage corresponding to the second frequency when the frequency switching instruction unit instructs to switch from the first frequency to the second frequency. A calculation step (S12);
A relationship between a waiting time indicating a time until the output voltage of the voltage output unit switches from the first voltage to the stabilized second voltage, and a voltage difference between the first voltage and the second voltage. A waiting time determining step (S14) for obtaining the waiting time voltage difference data in advance, and determining the waiting time based on the waiting time voltage difference data and the voltage difference calculated in the voltage difference calculating step;
A frequency switching information output step (S16) for outputting information indicating that the frequency has been switched when the waiting time determined in the waiting time determination step has elapsed since the voltage output unit outputs the second voltage; A frequency switching method comprising: In the voltage difference calculation step, when the frequency bands of the signals generated by the plurality of voltage controlled oscillators partially overlap each other and the second frequency is included in the overlapping frequency band, the second frequency is included. The first voltage difference between the voltage according to the second frequency and the first voltage in the voltage controlled oscillator that generates a signal in one frequency band, and the second voltage in the voltage controlled oscillator that generates a signal in the other frequency band. Calculating a voltage according to frequency and a second voltage difference between the first voltage,
5. The waiting time is determined based on a smaller voltage difference of the first voltage difference and the second voltage difference and the waiting time voltage difference data in the waiting time determining step. The frequency switching method described in 1. The voltage stabilizing unit includes a plurality of series circuits in which resistors and capacitors are connected in series, and a switch that selects one of the plurality of series circuits.
6. The frequency switching method according to claim 4, further comprising a time constant switching step of switching a time constant of the voltage stabilizing unit by switching the switch.

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