Range Bound Channel Index (RBCI) is calculated by means of the channel (bandwidth) filter (CF).

Channel filter simultaneously fulfills two functions: removes low frequent trend formed by low frequent components of the spectrum; removes high frequency noise formed by the high frequent components of the spectrum.

When RBCI approaches its local maximum the prices approach upper border of the trading channel and when RBCI approach its local minimum the prices approach the lower border of the trading corridor. Let’s mark main property of RBCI index. This is quasi stationary (that is almost stationary) process bound by the frequency range both from above and below.

(New Adaptive Method of Following the Tendency and Market Cycles by Vladimir Kravchuk)

//PRC_RBCI | indicator
//20.09.2018
//Nicolas @ www.prorealcode.com
//Sharing ProRealTime knowledge

// --- settings 
BBPeriod=100         //Period for Bollinger levels
// --- end of settings 

price = customclose

RBCI=-35.524181940 * price[0]-29.333989650 * price[1]-18.427744960 * price[2]-5.3418475670 * price[3]+7.0231636950 * price[4]+16.176281560 * price[5]+20.656621040 * price[6]+20.326611580 * price[7]+16.270239060 * price[8]+10.352401270 * price[9]+4.5964239920 * price[10]+0.5817527531 * price[11]-0.9559211961 * price[12]-0.2191111431 * price[13]+1.8617342810 * price[14]+4.0433304300 * price[15]+5.2342243280 * price[16]+4.8510862920 * price[17]+2.9604408870 * price[18]+0.1815496232 * price[19]-2.5919387010 * price[20]-4.5358834460 * price[21]-5.1808556950 * price[22]-4.5422535300 * price[23]-3.0671459820 * price[24]-1.4310126580 * price[25]-0.2740437883 * price[26]+0.0260722294 * price[27]-0.5359717954 * price[28]-1.6274916400 * price[29]-2.7322958560 * price[30]-3.3589596820 * price[31]-3.2216514550 * price[32]-2.3326257940 * price[33]-0.9760510577 * price[34]+0.4132650195 * price[35]+1.4202166770 * price[36]+1.7969987350 * price[37]+1.5412722800 * price[38]+0.8771442423 * price[39]+0.1561848839 * price[40]-0.2797065802 * price[41]-0.2245901578 * price[42]+0.3278853523 * price[43]+1.1887841480 * price[44]+2.0577410750 * price[45]+2.6270409820 * price[46]+2.6973742340 * price[47]+2.2289941280 * price[48]+1.3536792430 * price[49]+0.3089253193 * price[50]-0.6386689841 * price[51]-1.2766707670 * price[52]-1.5136918450 * price[53]-1.3775160780 * price[54]-1.6156173970 * price[55]

avg = average[BBperiod](RBCI)
dev = std[BBperiod](RBCI)
up1 = avg+dev
up2 = avg+dev*2
dn1 = avg-dev
dn2 = avg-dev*2

RETURN -RBCI coloured(176,23,31) style(line,3) as "RBCI", -up1 coloured(150,150,150) style(dottedline) as "up1", -up2 coloured(150,150,150) style(dottedline) as "up2", -dn1 coloured(150,150,150) style(dottedline) as "dn1", -dn2 coloured(150,150,150) style(dottedline) as "dn2"