JP2008256644A - Signal generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a signal generator capable of inhibiting an output of signal of excessive level user unintended when the output level of signal is altered. <P>SOLUTION: A delay setting section (63) sets out a delaying part only, into which ATT setting signal for establishing attenuators (31, 32, 33, and 34) to non-attenuation state is input, as a delayed state. The delay part (64) established as the delayed state delays the ATT setting signal to input into the attenuators, while the other delaying parts input the ATT setting signal into attenuators with no delay. Thereby, after a setting change is implemented of the attenuators to be established as attenuation state, setting change is implemented of the attenuators to be established as non-attenuation state. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  According to the present invention, in a signal generation device that generates a desired signal and controls and outputs the signal level, when the signal output level is changed, an excessive level signal that is not intended by the user is output. It is related with the technology to prevent.

  For example, a user-desired signal such as a CDMA modulation signal is output to a mobile terminal or base station at a level desired by the user, and the operation of the mobile terminal or base station is confirmed and tested. Signal generators are known.

  FIG. 7 shows the configuration of such a conventional signal generator 1. The signal generator 1 includes a signal generator 2, a level controller 3, a level designation unit 4 and a level setting unit 5.

  The signal generation means 2 reads waveform information from an internal memory or generates waveform information by internal calculation according to user settings, and outputs a signal desired by the user. However, the level of the signal output by the signal generation means 2 is fixed and is not controlled to the output level desired by the user.

  The level control means 3 includes a plurality of attenuators (ATT). In FIG. 7, the level control means 3 includes four attenuators ATTa31, ATTb32, ATTc33, and ATTd34 having different attenuation amounts.

  Here, as an example of the attenuator, FIG. 8 shows a configuration of the ATTa 31. The ATTa 31 is an electronic attenuator (E-ATT) that includes an attenuation element 31a and a changeover switch (SWa) 31b. The attenuation element 31a has a predetermined attenuation amount for each ATT, and the ATTa 31 has an attenuation amount of 5 dB. The change-over switch 31b can switch whether the signal input to the ATTa 31 is output as it is, or attenuated by the attenuation element 31a and output. This switching setting is set by an ATT setting signal A (described later) input from the outside of the ATTa 31. Here, a state in which the input signal is set to be output as it is is referred to as a non-attenuating state, and a state in which the input signal is output after being attenuated by the attenuating element 31a is referred to as an attenuating state.

  Returning to FIG. 7, the level specifying means 4 includes a button and a dial for the user to specify the output level of the signal to the signal generator 1, and a display on which the specified value is displayed for the user to confirm the specified output level. Etc. Note that power (unit: dBm) is normally used for designating the output level, but there are cases where the amplitude of the signal is designated or the attenuation amount of the level control means 3 is designated directly.

  The level setting means 5 includes an ATT setting unit 51 and an ATT setting table 52.

  As shown in FIG. 9, the ATT setting table 52 sets each attenuator ATTa31, ATTb32, ATTc33, and ATTd34 to the attenuation state or the non-attenuation state with respect to the set attenuation amount to be set in the level control means 3. The column with a mark indicates the attenuation state, and the blank column indicates the non-attenuation state.

  When the information on the output level designated by the user is received from the level designation means 4, the ATT setting section 51 should be set in the level control means 3 from this information and a predetermined output level of the signal generation means 2. Determine the set attenuation. Then, referring to the ATT setting table 52, the setting of each attenuator corresponding to the set attenuation amount is read, and the above-described ATT setting signal A is output to each attenuator.

  The level control means 3 attenuates the signal output from the signal generation means 2 by each attenuator and outputs the attenuated signal. The signal output from the level control means 3 is output as an output signal of the signal generator 1 to a mobile terminal or a base station (both not shown) as a test target.

The configuration of such a signal generator is disclosed in, for example, Patent Document 1.
JP-A-2005-249626

  However, such a conventional signal generator 1 has the following problems.

  FIG. 10 is an example of a timing chart when the set attenuation amount of the level control unit 3 is changed from 25 dB to 50 dB in order to change the output level of the signal output from the level control unit 3 in the conventional signal generator 1. It is. Before the level change, ATTa31 (5 dB) and ATTc33 (20 dB) are set in an attenuation state, and ATTb32 (10 dB) and ATTd34 (40 dB) are set in a non-attenuation state. After the level change, ATTa31 (5 dB) and ATTc33 (20 dB) are set to the non-attenuated state, and ATTb32 (10 dB) and ATTd34 (40 dB) are set to the attenuated state.

  First, upon receiving designation of the changed output level from the user, the ATT setting unit 51 outputs an ATT setting signal toward the attenuators ATTa31, ATTb32, ATTc33, and ATTd34 at the timing of (g). However, the time from when each attenuator receives the ATT setting signal to when the setting change is actually completed varies even with an attenuator of the same product. In the electronic attenuator used in each attenuator ATTa31, ATTb32, ATTc33, ATTd34 of the signal generator 1, the variation is about 1 μs, for example.

  For this reason, in the example of FIG. 10, the setting change of the ATTa 31 is first completed at the timing (h). Since ATTa 31 is an attenuation amount of 5 dB and is a setting change from the attenuation state to the non-attenuation state, the actual attenuation amount of the level control means 3 is reduced by 5 dB at this timing, and the level of the output signal from the level control means 3 is 5 dB. To increase.

  Next, the setting change of ATTc 33 is completed at the timing (i). Since ATTc 33 is an attenuation amount of 20 dB and is a setting change from the attenuation state to the non-attenuation state, the actual attenuation amount of the level control means 3 is reduced by 20 dB to 0 dB at this timing, and the output signal of the level control means 3 The level increases by 20 dB.

  At the timing (j), the setting change of ATTd34 is completed. Since ATTd34 has an attenuation amount of 40 dB and is a setting change from the non-attenuation state to the attenuation state, the actual attenuation amount of the level control unit 3 increases by 40 dB at this timing, and the level of the output signal from the level control unit 3 is 40 dB. descend.

  Similarly, at the timing (k), the setting change of the ATTb 32 is completed, the ATTb 32 has an attenuation of 10 dB, and the setting change from the non-attenuated state to the attenuated state. Therefore, the actual attenuation of the level control means 3 is 10 dB. It increases to 50 dB, which is the set attenuation after the setting change, and the change of the output level is completed.

  Here, during timing (h) to (j), the amount of attenuation is lower than the amount of attenuation 25 dB before the setting change, and particularly during timing (i) to (j), the amount of attenuation is 0 dB. ing. This means that the level of the output signal of the level control means 3 during that period is very high. The user only specifies the output level change so that the attenuation of the level control means 3 is changed from 25 dB to 50 dB, and it is assumed that the signal is output at an excessive level even instantaneously. Not done. When an output signal of such an excessive level is output, the operation of the mobile terminal or base station that is the output destination of the signal of the signal generator 1 may be malfunctioned, and an accurate test may not be performed. In the worst case, the mobile terminal or base station may be destroyed.

  An object of the present invention is to solve the above-described problems and to provide a signal generator that prevents an excessive level signal unintended by the user from being output when changing the signal output level. To do.

  In order to achieve the above-mentioned object, a signal generator (10) according to claim 1 of the present invention includes a signal generator (2) for generating and outputting a desired signal, and a predetermined attenuation amount and attenuation. The attenuator has a plurality of attenuators (31, 32, 33, 34) that can be set to either a state or a non-attenuated state, and the signal from the signal generating means is in the attenuated state. Level control means (3) for output after attenuation by the total attenuation amount, level designation means (4) for designating the output level of the signal output from the level control means, and designated by the level designation means In response to the level, an ATT setting signal (A) for setting the attenuator of the level control means to either the attenuation state or the non-attenuation state is sent to each of the plurality of attenuators. In the signal generating device including the level setting means having the ATT setting section for outputting, the level setting means (6) is provided between the ATT setting section and the plurality of attenuators of the level control means, respectively. A plurality of delay sections (64) that can be set to either a delay state in which the ATT setting signal is output after being delayed for a predetermined time or a non-delay state in which the ATT setting signal is output without being delayed, and specified by the level specifying means In response to setting information of the ATT setting signal output corresponding to the level, only the delay unit to which the ATT setting signal for setting the attenuator to the non-attenuating state is set to the delay state. A delay setting unit (63), and the ATT setting unit (61) responds to the new level when a new level is specified by the level specifying means. The delay setting unit notifies the delay setting unit of setting information of the ATT setting signal to be output, and outputs the ATT setting signal after the delay setting unit sets the delay unit. .

  The signal generator of claim 2 of the present invention is the signal generator of claim 1, wherein the delay setting unit is configured to receive the ATT setting signal for setting the attenuator from the attenuation state to the non-attenuation state. Only the input delay unit is set in a delay state.

  The signal generator according to claim 3 of the present invention is the signal generator according to claim 1 or 2, characterized in that the delay unit includes a shift register (64a) for delaying the ATT setting signal. To do.

  As described above, the signal generator according to the present invention delays the ATT setting signal A input to the attenuator that becomes the non-attenuating state after the setting change when changing the output level of the signal, and sets the attenuation state after the setting change. The ATT setting signal A input to the attenuator is not delayed so that the output level of the signal generator in the transient state of the signal output level change is higher before the output level change or after the output level change. Therefore, when changing the output level of the signal, it is possible to prevent an excessive level signal unintended by the user from being output.

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

(First embodiment)
FIG. 1 shows a configuration of a signal generator 10 to which the present invention is applied. In addition, about the structure similar to the conventional signal generator 1, the same code | symbol is attached | subjected and description is abbreviate | omitted suitably.

  The signal generation device 10 includes a signal generation unit 2, a level control unit 3, a level designation unit 4 and a level setting unit 6. Here, the signal generation means 2, the level control means 3, and the level designation means 4 have the same configuration as that of the conventional signal generator 1.

  The level setting means 6 includes an ATT setting unit 61, an ATT setting table 62, a delay setting unit 63, four delay units 64, an oscillator 65, and a frequency divider 66.

  The ATT setting table 62 has the same configuration as the ATT setting table 52 of the conventional signal generator 1, and each attenuator ATTa 31 corresponds to the set attenuation amount to be set in the level control means 3, as shown in FIG. , ATTb32, ATTc33, and ATTd34 are set to be in an attenuated state or a non-attenuated state, and a column with a mark indicates an attenuated state and a blank column indicates a non-attenuated state.

  When the information on the output level designated by the user is received from the level designation means 4, the ATT setting section 61 should be set in the level control means 3 from this information and a predetermined output level of the signal generation means 2. Determine the set attenuation. Then, referring to the ATT setting table 62, the setting information of each attenuator corresponding to the set attenuation amount is read, and the setting information of each attenuator is output to the delay setting unit 63 described later. The setting information of each attenuator is the setting information of each ATT setting signal A. When receiving the delay setting completion signal C from the delay setting unit 63, the ATT setting signal A is output to each attenuator of the level control means 3.

  The oscillator 65 outputs a clock signal having a predetermined frequency. Further, the frequency divider 66 divides the clock signal output from the oscillator 65 by a predetermined frequency dividing ratio and outputs it as a frequency-divided clock D. Here, if the frequency of the clock signal of the oscillator 65 is 33 MHz and the frequency division ratio of the frequency divider 66 is 4, the frequency of the frequency-divided clock D is 8.25 MHz.

  The delay unit 64 is provided corresponding to each of the attenuators ATTa31, ATTb32, ATTc33, and ATTd34 of the level control means 3, and when receiving the ATT setting signal A from the ATT setting unit 61, the delay unit 64 The ATT setting signal A is output with or without delay.

  FIG. 2 shows the configuration of the delay unit 64. The delay unit 64 includes a shift register 64a and a changeover switch (SWd) 64b.

  The shift register 64a has a predetermined number of bits and is input with a frequency-divided clock D. The ATT setting signal A input from the ATT setting unit 61 is shifted by 1 bit for each rising edge of the divided clock D, so that the ATT setting signal A is delayed and output. Here, assuming that the number of bits of the shift register 64a is n and the frequency of the divided clock D is f, the delay time Td of the ATT setting signal A by the shift register 64a is expressed by Td = n / f. The delay time Td is determined to be a value sufficiently larger than the time (for example, about 1 μs) from when the attenuators ATTa31, ATTb32, ATTc33, and ATTd34 receive the ATT setting signal A until the setting change is actually completed. For example, if the number of bits of the shift register 64a is 25 bits and the frequency of the divided clock D is 8.25 MHz, the delay time Td is about 3 μs. The delay time Td is determined according to the frequency of the oscillator 65, the frequency division ratio of the frequency divider 66, and the number of bits of the shift register 64a, and the designer may design it in consideration of hardware resources. For example, if the number of bits of the shift register 64a is 100 bits, the frequency division ratio of the frequency divider 66 is 1 (that is, the frequency divider is omitted), and the frequency of the oscillator 65 is 33 MHz, the delay time Td is about the same as the above example. 3 μs.

  The change-over switch 64b can switch whether the signal input to the delay unit 64 is output without being delayed or output after being delayed by the shift register 64a. This switching setting is set by a delay setting signal B input from a delay setting unit 63 described later. Here, a state in which the input ATT setting signal A is set to be output without delay is referred to as a non-delay state, and a state in which the input is set to be delayed by the shift register 64a is referred to as a delay state.

When the delay setting unit 63 receives the setting information of each attenuator from the ATT setting unit 61, the delay setting unit 63 determines from the setting information whether each attenuator is set in an attenuation state or a non-attenuation state. Then, a delay setting signal B for setting the delay unit 64 to the non-delay state is output toward the delay unit 64 corresponding to the attenuator set to the attenuation state. Further, a delay setting signal B for setting the delay unit 64 to the delay state is output toward the delay unit 64 corresponding to the attenuator set to the non-attenuating state. The delay setting unit 63 outputs the delay setting completion signal C to the ATT setting unit 61 after outputting the delay setting signal B to all the delay units 64.
The operation of the signal generator 10 configured as described above will be described with reference to FIG. FIG. 3 is a flowchart showing the operation of the signal generator 10 when changing the signal output level.

  First, the signal generator 10 is in a state where a signal desired by the user is output at an output level designated by the user. Here, in order to change the output level, the user designates the changed output level by the level designation means 4 (S1).

  When the information on the output level designated by the user is received from the level designation means 4, the ATT setting section 61 should be set in the level control means 3 from this information and a predetermined output level of the signal generation means 2. The set attenuation amount is determined, the setting information of each attenuator corresponding to the set attenuation amount is read with reference to the ATT setting table 62. Then, the setting information of each attenuator is output to the delay setting unit 63 (S2).

  When receiving the setting information of each attenuator from the ATT setting unit 61, the delay setting unit 63 first designates the ATTa 31 as the first attenuator (S3). Then, it is determined from this setting information whether the ATTa 31 is set to the attenuation state or the non-attenuation state (S4).

  When the ATTa 31 is set to the non-attenuating state (S4-YES), the delay setting unit 63 outputs the delay setting signal B for setting the delay state to the delay unit 64 corresponding to the ATTa 31 (S5). ). When the ATTa 31 is set to the attenuated state (S4-NO), the delay setting signal B for setting the non-delayed state is output to the delay unit 64 corresponding to the ATTa 31 (S6).

  Then, it is determined whether the determination for all attenuators is completed (S7). Here, since it is not completed (S7-NO), ATTb32 is designated as the next attenuator (S8), and it is determined whether this ATTb32 is set to the attenuation state or the non-attenuation state (S8). S4).

  In this way, when the determination for all attenuators is completed (S7-YES), the delay setting unit 63 outputs the delay setting completion signal C to the ATT setting unit 61. The ATT setting unit 61 receives the delay setting completion signal C and outputs each ATT setting signal A (S9).

  Each delay unit 64 is set to either a delay state or a non-delay state by a delay setting signal from the delay unit 63, thereby delaying the ATT setting signal A from the ATT setting unit 61, or Without delay, the data is output to each attenuator ATTa31, ATTb32, ATTc33, ATTd34 (S10).

  Each of the attenuators ATTa31, ATTb32, ATTc33, and ATTd34 is set to one of the attenuation state and the non-attenuation state. Is output (S11).

  FIG. 4 shows an example of a timing chart when the set attenuation amount of the level control means 3 is changed from 25 dB to 50 dB in order to change the level of the signal output from the level control means 3 in the signal generator 10 of the present invention. It is.

  Before the change, ATTa31 (5 dB) and ATTc33 (20 dB) are set in the attenuation state, and ATTb32 (10 dB) and ATTd34 (40 dB) are set in the non-attenuation state. After the change, ATTa31 (5 dB) and ATTc33 (20 dB) are set to the non-attenuated state, and ATTb32 (10 dB) and ATTd34 (40 dB) are set to the attenuated state.

  First, in response to a change in the designation of the output level from the user, the ATT setting unit 61 outputs an ATT setting signal A toward each attenuator ATTa31, ATTb32, ATTc33, ATTd34 at the timing (a). Among these, for ATTb32 and ATTd34, since the changed state is set to the attenuated state, the corresponding delay unit 64 is set to the non-delayed state. Therefore, the ATT setting signal A is input to ATTb32 and ATTd34 without being delayed. On the other hand, for ATTa 31 and ATTc 33, since the changed state is set to the non-attenuating state, the corresponding delay unit 64 is set to the delayed state, and the ATT setting signal A is delayed, which will be described later (d). Are input to ATTa31 and ATTc33.

  The time from when the ATT setting signal A is received to when the setting change is actually completed varies as described above, and the setting change of the ATTd 34 is first completed at the timing (b). Since ATTd34 is an attenuation amount of 40 dB and is a setting change from the non-attenuation state to the attenuation state, the actual attenuation amount of the level control means 3 increases by 40 dB to 65 dB at this timing, and the output signal of the level control means 3 The level drops by 40 dB.

  Next, the setting change of ATTb32 is completed at the timing of (c). Since ATTb32 has an attenuation of 10 dB and is a setting change from the non-attenuated state to the attenuated state, at this timing, the actual attenuation of the level control unit 3 increases by 10 dB to 75 dB, and the output signal from the level control unit 3 The level is reduced by 10 dB.

  (D) is the timing when the delay time Td in the shift register 64a of the delay unit 64 has elapsed from the timing of (a). At this timing (d), the ATT setting signal A is input to ATTa31 and ATTc33. Since the delay time Td is determined in consideration of the variation in time from when the ATT setting signal A is received until the setting change is actually completed, at the timing (d), ATTb32 and ATTd34 complete the setting change. is doing.

  At the timing (e), the setting change of the ATTa 31 is completed. Since ATTa31 is an attenuation amount of 5 dB and is a setting change from the attenuation state to the non-attenuation state, the actual attenuation amount of the level control means 3 is reduced by 5 dB to 70 dB at this timing, and the output signal from the level control means 3 The level increases by 40 dB.

  Similarly, at the timing of (f), the setting change of ATTc33 is completed, and ATTc33 is an attenuation amount of 20 dB, and the setting change from the attenuation state to the non-attenuation state is performed. Therefore, the actual attenuation amount of the level control means 3 is 20 dB. It decreases to 50 dB which is the set attenuation after the setting change, the level of the output signal from the level control means 3 increases by 20 dB, and the change of the output level is completed.

  As described above, in the signal generator 10 according to the first embodiment, when changing the output level of the signal, the ATT setting signal A input to the attenuator that is in the non-attenuating state after the setting change is delayed to change the setting. The ATT setting signal A that is input to the attenuator that is to be attenuated later is not delayed. As a result, the setting change of the attenuator that becomes the attenuation state after the setting change is performed first, and then the setting change of the attenuator that becomes the non-attenuating state after the setting change is performed, so in the transient state of the setting change, the level control means The attenuation amount 3 does not become lower than the lower one of the attenuation amount before the setting change and the attenuation amount after the setting change. That is, the output level of the signal generator 10 in the transition state of the setting change is never higher than the higher output level before the output level change or after the output level change. For this reason, when changing the output level of a signal, it is possible to prevent an excessive level signal unintended by the user from being output.

  The delay of the ATT setting signal A in the delay unit 64 is realized by using the shift register 64a. The delay time Td is the frequency of the oscillator 65, the frequency division ratio of the frequency divider 66, and the number of bits of the shift register 64a. It is decided according to. For this reason, the delay time Td is a value sufficiently larger than the time from when each attenuator ATTa31, ATTb32, ATTc33, ATTd34 receives the ATT setting signal A until the setting change is actually completed, and an appropriate value that is not excessive. Can be set to When such control is realized by software, it takes several tens of μs to complete the control. In this embodiment, the level setting means 6 is configured by an FPGA and is hardware-processed, so that the delay time Td can be prevented from becoming excessive. As a result, the state of each attenuator in the level control means 3 can be prevented. Switching can be performed at a higher speed than control by software. That is, the output level of the signal generator 10 can be switched at high speed while preventing an excessive level signal unintended by the user from being output.

(Second Embodiment)
FIG. 5 shows a configuration of a signal generator 10 according to another embodiment to which the present invention is applied. Note that description of the same configuration as that of the above-described embodiment will be omitted as appropriate.

  The signal generation device 10 includes a signal generation unit 2, a level control unit 3, a level designation unit 4 and a level setting unit 6. Here, the signal generation means 2, the level control means 3, and the level designation means 4 have the same configuration as in the above-described embodiment.

  The level setting means 6 includes an ATT setting unit 61, an ATT setting table 62, a delay setting unit 63, four delay units 64, an oscillator 65, a frequency divider 66, and an ATT setting storage unit 67. The ATT setting table 62, the four delay units 64, the oscillator 65, and the frequency divider 66 have the same configuration as that of the above-described embodiment.

  The ATT setting storage unit 67 stores the current setting information of each attenuator.

  When the delay setting unit 63 receives the setting information of each attenuator from the ATT setting unit 61, the delay setting unit 63 is currently in the attenuation state among the attenuators from the setting information and the current setting information stored in the ATT setting storage unit 67. It is determined whether there is an item that has been set and is set to a non-attenuating state after the setting is changed. Then, a delay setting signal B for setting the delay unit 64 to the delay state is output toward the delay unit 64 corresponding to the attenuator whose setting is changed from the attenuation state to the non-attenuation state. Further, a delay setting signal B for setting the delay unit 64 to the non-delay state is output toward the delay unit 64 corresponding to the other attenuators. The delay setting unit 63 outputs the delay setting signal B to all the delay units 64 and then updates the setting information of each attenuator in the ATT setting storage unit 67 and sends the delay setting completion signal C to the ATT setting unit 61. Output.

  The operation of the signal generator 10 configured as described above will be described with reference to FIG. FIG. 6 is a flowchart showing the operation of the signal generator 10 when changing the signal output level.

  First, the signal generator 10 is in a state where a signal desired by the user is output at an output level set by the user. Here, in order to change the output level, the user designates the changed output level by the level designation means 4 (S21).

  When the information on the output level designated by the user is received from the level designation means 4, the ATT setting section 61 should be set in the level control means 3 from this information and a predetermined output level of the signal generation means 2. The set attenuation amount is determined, the setting information of each attenuator corresponding to the set attenuation amount is read with reference to the ATT setting table 62. Then, the setting information of each attenuator is output to the delay setting unit 63 (S22).

  Upon receiving the setting information for each attenuator from the ATT setting unit 61, the delay setting unit 63 first designates ATTa 31 as the first attenuator (S23).

  Then, referring to the ATT setting storage unit 67, it is determined from the setting information in the ATT setting storage unit 67 whether the ATTa 31 is currently set in an attenuation state or a non-attenuation state (S24).

  When the ATTa 31 is currently set to the non-attenuating state (S24-NO), the delay setting unit 63 sends the delay setting signal B for setting the non-delaying state toward the delay unit 64 corresponding to the ATTa 31. Output (S27). If the ATTa 31 is currently set in the attenuated state (S24-YES), the delay setting unit 63 determines whether the ATTa 31 is set in the attenuated state based on the setting information of each attenuator received from the ATT setting unit 61. Then, it is determined whether the non-attenuating state is set (S25). When the ATTa 31 is set to the attenuated state (S25-NO), the delay setting signal B for setting the non-delayed state is output toward the delay unit 64 corresponding to the ATTa 31 (S27). When the ATTa 31 is set to the non-attenuating state (S25-YES), the delay setting signal B for setting the delay state is output toward the delay unit 64 corresponding to the ATTa 31 (S26).

  Then, it is determined whether the determination for all attenuators is completed (S28). Here, since it is not completed (S28-NO), ATTb32 is designated as the next attenuator (S29), and the determination for ATTb32 is performed (S24).

  When the determination for all attenuators is completed in this way (S28-YES), the delay setting unit 63 updates the setting information of each attenuator in the ATT setting storage unit 67 and sets the delay toward the ATT setting unit 61. A completion signal C is output. The ATT setting unit 61 receives the delay setting completion signal C and outputs each ATT setting signal A (S30).

  Each delay unit 64 is set to either a delay state or a non-delay state by a delay setting signal B from the delay unit 63, thereby delaying the ATT setting signal A from the ATT setting unit 61, Alternatively, the data is output to each attenuator ATTa31, ATTb32, ATTc33, ATTd34 without delay (S31).

  Each of the attenuators ATTa31, ATTb32, ATTc33, and ATTd34 is set to any one of the attenuation state and the non-attenuation state. As a result, the signal of the output level designated by the user as the output level after the change is sent from the signal generator 10. It is output (S32).

  In the signal generator 10 according to the second embodiment configured as described above, the ATT setting signal input to the attenuator whose setting is changed from the attenuation state to the non-attenuation state when the signal output level is changed. The configuration is such that A is delayed and the ATT setting signal A input to the other attenuators is not delayed. As a result, the attenuator whose setting is changed from the non-attenuated state to the attenuated state, the attenuator that remains in the attenuated state even when the setting is changed, and the attenuator that remains in the non-attenuated state even when the setting is changed are changed first. Then, since the setting change of the attenuator to change the setting from the attenuation state to the non-attenuation state is performed, in the transient state of the setting change, the attenuation amount of the level control means 3 is the same as the attenuation amount before the setting change and the setting change. It will never be lower than the later attenuation, whichever is lower. That is, the output level of the signal generator 10 in the transition state of the setting change is never higher than the higher output level before the output level change or after the output level change. For this reason, when changing the output level of a signal, it is possible to prevent an excessive level signal unintended by the user from being output. Further, since the ATT setting signal A is delayed only for the attenuator whose setting is changed from the attenuated state to the non-attenuated state, all the ATT setting signals are changed when the output level is changed without the corresponding attenuator. Since A becomes non-delayed, the output level can be changed at high speed.

It is a figure which shows the structure in one Embodiment of the signal generator by this invention. It is a figure which shows the structure of a delay part. It is a figure which shows the operation | movement flow of the output level change in one Embodiment. It is a figure which shows the timing chart in output level change. It is a figure which shows the structure in other embodiment of the signal generator by this invention. It is a figure which shows the operation | movement flow of the output level change in other embodiment. It is a figure which shows the structure of the conventional signal generator. It is a figure which shows the structure of an attenuator. It is a figure which shows the content of the ATT setting table. It is a figure which shows the timing chart of the conventional signal generator.

Explanation of symbols

  2 ... signal generation means, 3 ... level control means, 4 ... level designation means, 6 ... level setting means, 31, 32, 33, 34 ... attenuator (ATT), 61 ... ATT setting section, 62 ... ATT setting table, 63 ... Delay setting section, 64 ... Delay section, 64a ... Shift register, 64b ... Changeover switch (SWd), 65 ... Oscillator, 66 ... Frequency divider, 67 ... ATT setting storage section

Claims (3)

Signal generating means (2) for generating and outputting a desired signal;
A plurality of attenuators (31, 32, 33, 34) each having a predetermined amount of attenuation and settable in either an attenuation state or a non-attenuation state, and the signal from the signal generation means; Level control means (3) for attenuating by the total attenuation amount of the attenuator in the attenuation state,
Level specifying means (4) for specifying the output level of the signal output from the level control means;
In response to the level designated by the level designation means, an ATT setting signal (A) for setting the attenuator of the level control means to either the attenuation state or the non-attenuation state is provided to each of the plurality of attenuators. In a signal generation device comprising level setting means having an ATT setting unit for output,
The level setting means (6)
One of a delay state provided between the ATT setting unit and the plurality of attenuators of the level control means and outputting the ATT setting signal with a delay for a predetermined time and a non-delay state for outputting without delay. A plurality of delay units (64) that can be set to
The delay unit to which the ATT setting signal for setting the attenuator to the non-attenuating state is input in response to setting information of the ATT setting signal output corresponding to the level specified by the level specifying means A delay setting unit (63) for setting only the delay state to the delay state,
The ATT setting unit (61)
When a new level is specified by the level specifying means, the delay setting unit notifies the delay setting unit of setting information of the ATT setting signal to be output in correspondence with the new level, and the delay setting unit A signal generator (10) characterized in that the ATT setting signal is output after the setting to the unit is performed. The delay setting unit includes:
2. The signal generation device according to claim 1, wherein only the delay unit to which the ATT setting signal for setting the attenuator from the attenuation state to the non-attenuation state is input is set to a delay state. The delay unit is
3. The signal generator according to claim 1, further comprising a shift register for delaying the ATT setting signal.

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