Determination of type SVX8 speed of sound signal source transmitting power, and wide frequency range, waveform types, and
Stability in the work of a small distortion; receive high gain, clear Oscillographic stability, volatility around in 12V, not
Rely on the oscilloscope to enlarge; clever signal processing peculiar to operate enriched content, the new screen Oscillographic
Ying lively and stimulating interest in learning, inspire innovative thinking. Figure 8 show the measured speed of sound SVX8 type letter
Its front panel source, panel upper two figures below:
(1) the left is a 8-bit LED frequency / time difference table in the standing wave method used to measure the phase law
Frequency f, show the units are kHz (kHz), there are three decimal; the difference method used to measure the time difference t, display units are microseconds (μs), there are three decimal places.
(2) the right is a three half-LED peak voltage meter to monitor the signal source at any time of the output
Strong or weak. The reason why the peak measured RMS unexpected because the output signal not only sinusoidal waveform, as well as triangular, rectangular and the pulse.
The lower part of Figure 8 are connected to control components and parts, from left to right:
(3) "Oscillographic launch", "receive Oscillographic" two sockets at the bottom of the left panel to insert the plug Q9 and Q9 plug the coaxial cable connected to the signal sent to the oscilloscope to show that in general, the "launch "to the channel CH1," receiver "to the channel CH2. See the Figure 2. To confirm that contact patch when the good in order to avoid interference wave.
(4) "wave" switch from the "sine, triangular, rectangular, step, wave out" 5 files
Launched to select a file as a waveform, transported to the "launching" socket (far right), at the same time
Also transported to the "launching Oscillographic" socket (far left).
The "step" wave needs a little note. Real step-wave is as follows: set
Under the jump (rise in the same token) where the time step for t, then - ∞ ~ t of the interval, the amplitude-heng 1; t ~ + ∞ in the interval, the amplitude of Constant to 0. Just a step under the jumpevents, there is no way to do in the oscilloscope display cyclical scan. If the next hop after the moment the slow rise from 0 to 1, you can jump for the second time under the conditions that Oscillographic cycle, but also step into a sawtooth wave. This experiment is to use an alternative step sawtooth wave approximation, the steep jump next to the transmitter along a strong incentive moment; 0.01 seconds and up to the rising edge of the slope is very small, the incentive for the role of transmitters can be neglected. Saw this experiment is not displayed on oscilloscopes, but the location of the next hop on the show along a narrow rectangular pulse, so that some of the aesthetic image. In addition to step-wave, the other four kinds of wave launching emission display waveform and waveforms are consistent.
     In addition, when the "wave" 1,2,3 switch placed in the first file, the top 8

Comparison of measured phase velocity
Connection is still experimental apparatus as shown in Figure 2, Chi oscilloscope function that the X-Y means Lissajous graphics. When the transmitter ultrasonic plane S1 issued through the media to reach the receiver S2, to receive the phase-wave backward wave will launch a phase angle
                                 (5)
Can be obtained by measuring the speed of sound to come. Determination of the vibration perpendicular available Lissajous synthesis for graphics. The following mathematical derivation.
X-channel oscilloscope input (that is, CH1) of the signal transmitter and the input signal S1 is the same as for its vibration equation:
                                              (6)
Y-channel input (ie, CH2) signal is received by the receiver to the volatility of S2, the vibration equation is:
                                              (7)
Where two, A1 and A2, respectively, for the screen on the X, Y direction of the vibration amplitude; for the angular frequency; and were X, Y direction of the early phase of vibration, the vibration equation for synthesis of
                      (8)
This equation for the elliptical trajectory, long oval, short-axis and the direction decided by the phase difference. When = 0, from (8) type a, that is, at the track for the first and third quadrant of a straight line, it is clear the slope of a straight line. Figure 4 (left) as shown; when = when, too, the track for the second and fourth quadrants in a straight line in Figure 4 (bottom right) shown. S1 and S2 changes the distance between the L, the equivalent of changing the wave launching and receiving the digital difference between waves, the graphics on the screen is also changing with the L. Clearly, when the S1, S2 to increase or decrease the distance between the half wavelength, the phase angle change =.