簡易波動指標（EMV）

簡易波動指標（Ease of Movement ）是由Richard W Arms開發，原理類似於等成交量圖。它突出了成交量與價格之間的關系，可以非常有效的衡量趨勢的強度。

該指標表現了：
• 如果較少的成交量就能推動股價上漲，則EMV數值會升高；
• 如果股價下跌時也僅伴隨較少的成交量，則EMV數值將降低；
• 如果價格波動小，或者價格的上漲和下跌都伴隨著較大的成交量時，則EMV的數值會趨近於零。意味著價格的分散（賣方市場）或集聚（買方市場）。

交易信號

交易信號通常是由EMV指標窗口中的指數移動平均線（EMA）得出。它們在趨勢交易中效果顯著。
• EMV自下而上穿透零軸時做多。
• EMV自上而下穿透零軸時做空。

示例：

可口可樂公司股價以及 EMV、 10日EMA. 

1. [L] 處做多：EMV上穿到零軸之上。
2. [S] 處做空：EMV穿至零軸之下。
3. [S] 處做空：需要註意的是，我們在市場調整期頻繁的被掃損。

計算公式
EMV的計算步驟為：
1. 計算每日價格的中值。
           (最高價 + 最低價) / 2
2. 計算出中值的波動：
          今日的中值—昨日的中值
3. 計算出等成交量柱狀圖的高與寬的比值：
           成交量（百萬）/（最高價—最低價）
4. EMV值為：
           中值的變動量 / 長寬比
5. EMV通常結合14日EMA使用。

Ease of Movement
Ease of Movement was developed by Richard W Arms and performs a similar function to Equivolume charts. It highlights the relationship between volume and price changes and is particularly useful for assessing the strength of a trend.
The indicator shows:
• high positive values when prices move upward on light volume;
• high negative values when prices move down on light volume;
• low values if price is not moving or if it takes heavy volume to move prices, signaling distribution oraccumulation.
Trading Signals
Signals are normally taken from an exponential moving average plotted on the Ease of Movement indicator. They are more effective in a trending market.
• Go long when Ease of Movement crosses to above zero (from below).
• Go short when Ease of Movement crosses to below zero (from above).
EXAMPLE
Coca Cola Corporation plotted with   Ease of Movement indicator smoothed by a
  10 day exponential moving average.
1. Go long [L]: Ease of Movement crosses to above zero.
2. Go short [S]: Ease of Movement crosses to below zero.
3. Go long [L]: Ease of Movement crosses to above zero.
4. Go short [S]: Ease of Movement crosses to below zero.
5. Go long [L]: Ease of Movement crosses to above zero.
6. Go short [S]: Note that we are whipsawed more frequently in a ranging market.
Setup
The Ease of Movement default is set at 10 days smoothing by an exponential moving average. To alter the default settings - Edit Indicator Settings.
See Indicator Panel for directions on how to set up an indicator.
Formula
The steps in calculating Ease of Movement are:
1. Calculate the Mid-point for each day:
           (High + Low) / 2
2. Calculate the Mid-point Move for each day:
           Mid-point [today] - Mid-point [yesterday]
3. The Box Ratio determines the ratio between height and width of the Equivolume box:
           Volume [in millions] / (High - Low)
4. Ease of Movement is then calculated as:
           Mid-point Move / Box Ratio
5. Ease of Movement is normally smoothed with a 14 day exponential moving average.

本文翻譯由兄弟財經提供

文章來源：http://www.incrediblecharts.com/indicators/ease_of_movement.php