Radar & Sonar Masterclass – Billy Sir

Radar & Sonar Masterclass
雷達與聲納大師課

Billy Sir’s Interactive Physics: Time-of-Flight & Two-Pulse Method.
物理化學 Billy Sir 互動物理：飛行時間測距與雙脈衝測速

1. Finding Distance (Time of Flight) 測量距離 (飛行時間)

The device sends out a short burst of energy and starts a timer. When the pulse hits the target, it bounces back. The device stops the timer when it hears the echo. 設備發出短促的能量脈衝並啟動計時器。當脈衝擊中目標時會反彈。設備在接收到回聲時停止計時。

Target Distance 目標距離 500 m

Calculate It | 自行計算

Fire the pulse, read the stopwatch, and enter the data below. 發射脈衝，讀取秒錶，並在下方輸入數據以計算距離。

$$ \text{Distance} = \frac{v \times t}{2} $$

Wave Speed ($v$) in m/s 波速

Recorded Time ($t$) in µs 記錄時間

Calculated Distance | 計算結果

0 m

2. Finding Speed (Two-Pulse Method) 測量速度 (雙脈衝法)

The device measures the distance once ($d_1$), waits a tiny fraction of a second ($\Delta t$), and measures the distance again ($d_2$). The difference in distance over time gives the speed. 設備測量一次距離 ($d_1$)，等待極短的時間 ($\Delta t$)，然後再次測量距離 ($d_2$)。距離差除以時間即為速度。

Target Direction 目標方向

Target Speed 目標速度 30 m/s

Time Gap ($\Delta t$) 測量間隔 0.5 s

The Physics | 物理原理

$$ v_{\text{target}} = \frac{|d_1 – d_2|}{\Delta t} $$

Click “Measure Speed” to see the calculation.
點擊「測量速度」查看計算結果。