JP2000180482A - Frequency variation computing unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a frequency variation computing unit to obtain the acceleration of a rotator, a linearly moving body to be measured, etc., by receiving the input of frequency pulses to be measured from a pulse generating-type detector, etc., mounted to the rotator and the linearly moving body to be measured and obtaining frequency fluctuations. SOLUTION: In a frequency variation computing unit, each of the input of frequency pulses to be measured which vary every moment and the values latched by the input of the frequency pulses to be measured immediately before gates of an input pulse counter 6, which counts the frequency pulses to be measured for every time-gate between time-gates, and a free running counter 4, which counts time-base clocks 3, are inputted to an FIFO register 8, which shifts at every time-gate. Then the time stamp value of a few times (n-times) before, the time stamp value of this time, the sum value of the frequency pulses to be measured counted between the two time stamp values, and the time-base clocks are computed at a computing unit 7 and are obtained by acceleration computations.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating body or a linearly moving object which receives a frequency pulse to be measured from a pulse generating type detector or the like attached to a rotating body or a measuring object which moves linearly. The present invention relates to a frequency fluctuation calculator for obtaining an acceleration of a measured object or the like.

[0002]

2. Description of the Related Art In general, a frequency pulse to be measured is inputted from a pulse generating type detector or the like attached to a rotating body or a linearly moving object to be measured, and a frequency fluctuation is obtained to obtain a rotating or linearly moving object to be measured. In the case where the acceleration is calculated by analog calculation, the frequency is converted into a voltage by the frequency-voltage converter (30) and then converted into an acceleration signal by the differentiating circuit (31) as shown in FIG. are doing.

[0003]

However, as described above, the frequency is converted into a voltage by the frequency-voltage converter (30) as in the embodiment of FIG. In the case of conversion to the following, drift due to temperature change and aging change, loss of accuracy due to resistance, capacitor, etc., self-oscillation of the analog amplifier, poor responsiveness by a correction circuit for preventing self-oscillation, frequency-voltage converter (30 In the frequency-voltage conversion of (3), the problem of ripple in a low frequency region, and when the frequency is converted from the period measurement, the change of the step-like output voltage is determined by a differentiating circuit (3).
Steep rising output error due to differentiation in 1),
There are problems such as a delay in response by a first-order delay circuit for preventing a steep rising output error.

The present invention has been made in view of the above circumstances, and when the acceleration is determined from the frequency pulse to be measured which is input every moment, the accuracy is lost due to drift due to temperature changes and aging, and resistance and capacitors. Frequency fluctuation calculation by acceleration calculation that solves the problem of analog amplifier self-oscillation, poor response by correction circuit to prevent self-oscillation, etc., and enables calculation with high accuracy, stability and responsiveness It is intended to provide a container.

[0005]

In the frequency fluctuation calculator according to the present invention, as shown in the system diagram of FIG. 1, a frequency pulse to be measured (9) is input to generate a time gate. A gate clock (1), an input pulse counter (6) for counting a frequency pulse to be measured (9), a free running counter (4) for counting a time base clock (3), and a frequency pulse to be measured ( 9) A latch circuit (5) for latching the count value of the free running counter (4) at the input, and an F for storing the values of the input pulse counter (6) and the latch circuit (5) for each gate clock (1).
It comprises an IFO register (8), and a calculator (7) for taking out the stored value of the FIFO register (8) and calculating a time base clock (3) to obtain an acceleration.

[0006] According to the frequency fluctuation calculator of the above means, the input of the frequency pulse to be measured (9), which is constantly changing, is input to the predetermined time gate of the gate clock (1) for each time gate. The value of the input pulse counter (6) counting the frequency pulse (9) to be measured and the frequency pulse (9) immediately before the time gate of the free-running counter (4) counting the time base clock (3). ) Count value latched by input (time stamp value)
Are input to a FIFO register (8) that shifts each time gate of the gate clock (1), and the time stamp value of several times (n times), the current time stamp value, and the time stamp value are counted during that time. The sum of the frequency pulse to be measured (9) and the time base clock are calculated by the calculator (7) to obtain a frequency fluctuation calculation output obtained by the acceleration calculation.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a frequency fluctuation calculator according to the present invention. FIG. 1 is a system diagram showing a frequency fluctuation calculator according to the present invention and an embodiment thereof, and FIG. 2 is a timing explanatory diagram of FIG.

In FIG. 1, a gate clock (1) is a time gate for counting, measuring and calculating the whole, and the control circuit (2) bears the entire timing. This signal is
The time base clock (3) may be generated by dividing or may be generated asynchronously. Accuracy is not very important.

The time base clock (3) is a signal used as a reference for measuring the frequency pulse (9) to be measured, and is usually preferably at least 1000 times the frequency of the gate clock (1). This signal is constantly counted by the free running counter (4). The number of bits in the free running counter is set to be sufficiently long because carry is counted by software processing such as a microcomputer.

The latch circuit (5) latches the count value of the free-running counter (4), which is counting by the time base clock (3), with the signal of the frequency pulse to be measured (9). The latch data uses the value immediately before the gate clock (1) is input. The data of the latch circuit is
Send to IFO register (8).

The input pulse counter (6) constantly counts the frequency pulse (9) to be measured and uses the value immediately before the gate clock (1) is input. The value immediately before the gate clock (1) is input is sent to the FIFO register (8).

The FIFO register (8) is a first-in first-out register, and is usually controlled by a microcomputer, so that a memory or the like is used. Here, the value of the latch circuit (5) and the value of the input pulse counter (6) that are input for each gate clock (1) are shifted and input to the FIFO register (8).

The arithmetic unit (7) is usually realized by a microcomputer. The arithmetic unit (7) has the frequency of the time base clock (3) as an internal constant, and stores the current memory value and the previous (n-th previous) value from the FIFO register (8). The frequency and acceleration are calculated from the memory value.

Next, the operation of the above configuration will be described with reference to the timing diagram of FIG. The time in FIG. 2 is the past on the left and the present on the right.

The time base clock waveform (10) from the time base clock (3) is continuously counted by the free running counter (4).

The pulse waveform of the frequency to be measured (1
2) is counted continuously by the input pulse counter (6) as shown by the input pulse counter timing (14).

The pulse waveform of the frequency to be measured (1
At the timing of 2), the timing of the latch circuit (13)
As shown by, the time stamp value of the free running counter (4) counting the time base clock (3) is latched.

When the gate clock (1) is generated, the timing of the measurement interval is set as shown in the gate clock waveform (11).

As shown in a timing (15) immediately before the rising of the gate clock waveform (11) and immediately before the gate clock, the time stamp value of the latch circuit (5) and the frequency pulse to be measured ( The count value of 9) is shifted and sent to the FIFO register (8).

The frequency operation section (16) indicates a break for each gate clock. TM = frequency calculation section (16)
, But may be calculated at the timing of the end part.

TCK = time base clock waveform (1
0) frequency [Hz], FIN = frequency [Hz] of frequency pulse waveform to be measured (12), TST1 = FIFO register (8) REG1 data time stamp value from latch circuit (5), PIN1 = FIFO register ( 8) R
The value of the input pulse counter (6) of the EG1 data is assumed to be the current value of each.

In the frequency calculation, FIN = the number of input pulses in a section / the effective time in a section, and therefore, is calculated by the following equation.

[0023]

(Equation 1)

When n = 2, the frequency is within one gate clock period. A moving average for each gate clock is obtained when n = 3 or more.

Since the acceleration is calculated as follows: acceleration = (current frequency−previous frequency) / elapsed time, it is calculated by the following equation.

[0026]

(Equation 2)

The above operation is performed while shifting the FIFO register (8) and calculating by the calculator (7) for each gate clock (1).

As described above, when the time stamp value is used without stopping and resetting the free running counter (4), in the case of a long moving average, all FIFOs are used.
It is not necessary to add the value of the register (8) to perform the operation.

Furthermore, since the free running counter (4) is not stopped and reset, addition errors can be prevented. Of course, the calculation may be performed after stopping or resetting.

In this timing description, as shown in the timing (15) immediately before the rise of the gate clock waveform (11) and immediately before the gate clock (11), the latch circuit (5)
Is used, and the count value of the frequency pulse to be measured (9) of the input pulse counter (6) is used, but the timing immediately after the gate clock may be used.

As a method of not performing the averaging operation, the time base clock (3) is counted at each timing as shown by the frequency pulse waveform to be measured (12) without using the time gate of the gate clock (1). Latch circuit (5) for latching time stamp value of running counter (4)
Using the previous time stamp value and the current time stamp value indicated by the timing (13) of the latch circuit, the period can be measured to calculate the frequency and acceleration.

In this case, the gate clock (1), the input pulse counter (6), and the averaging register of the FIFO register (8) become unnecessary.

Further, since the gate clock (1) is not required, the FI is not used for the moving average calculation for each gate time, but at the timing shown in the timing (13) of the latch circuit.
A pulse-averaged moving average can also be sent by sending it to the FO register (8) for each input of the measured frequency pulse (9).

It should be noted that the frequency fluctuation calculator of the present invention is not limited to the above-described embodiment, and it is needless to say that various changes can be made without departing from the gist of the present invention.

[0035]

As described above, the first aspect of the present invention is as described above.
According to the described frequency fluctuation calculator, the frequency fluctuation calculation to obtain the acceleration by inputting the frequency pulse to be measured solves the problem of the calculation to calculate the acceleration from the frequency that was conventionally large, and the accuracy is improved even from a low time base. It is possible to achieve an excellent effect of enabling high-stability, high-resolution computation, and also performing optimal averaging processing.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an embodiment of a frequency fluctuation calculator according to the present invention.

FIG. 2 is a diagram showing an embodiment of a frequency fluctuation calculator according to the present invention.
FIG. 4 is a timing explanatory diagram of the configuration of FIG.

FIG. 3 is a system diagram showing an embodiment of an analog frequency fluctuation calculator using a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Gate clock 2 Control circuit 3 Time base clock 4 Free running counter 5 Latch circuit 6 Input pulse counter 7 Operation unit 8 FIFO register 10 Time base clock waveform 11 Gate clock waveform 12 Frequency pulse waveform to be measured 13 Latch circuit timing 14 Input pulse Counter timing 15 Timing immediately before the gate clock 16 Frequency calculation section 17 Acceleration calculation section without moving average 18 Two moving average acceleration calculation sections 19 Four moving average acceleration calculation sections 30 Frequency-voltage converter 31 Differentiating circuit

Claims (3)

[Claims] 1. A period / elapsed time is obtained from a count value obtained by inputting a frequency pulse to be measured and time base counting means for counting a time base clock of a reference frequency generating means with the input of the frequency pulse to be measured. A frequency variation calculator for calculating frequency and acceleration. 2. A frequency-measured pulse is input, and a count value obtained by latching the time-base counting means for counting the time-base clock of the reference frequency generating means with the frequency-of-measurement pulse input is provided for each frequency-of-measurement-pulse input. The data is input to the storage means of the FIFO (first-in first-out) operation to be shifted, and the time stamp value several times (n times) and the current time stamp value, and the total value of the frequency pulse to be measured counted during the time stamp value are stored. A frequency variation calculator for calculating a frequency and an acceleration for each input of a frequency pulse to be measured. 3. The method according to claim 1, wherein the frequency pulse to be measured is input, and for each time gate of the time counting means, the value of the pulse counting means for counting the frequency pulse to be measured between the time gates and the time of the reference frequency generating means. A FIFO (first-in-first-out) which shifts each of the count values (time stamp values) latched by the frequency pulse to be measured immediately before the time gate of the time base counting means for counting the base clock for each time gate of the time counting means. Out) input to the operation storage means to calculate the time stamp value several times (n times) and the current time stamp value, the total value of the frequency pulse to be measured counted during the time stamp, and the time base clock A frequency fluctuation calculator for obtaining a frequency and an acceleration for each time gate.