Please enter valid numeric values in all required fields.
Formulas & Mathematical Logic
Original formula preserved:
Crestfactor = Pmax / Pavg
ACPR = -20.75 + (1.6 × Crestfactor) + (2 × (Pin - IP3))
Pmax = peak power in dBm.
Pavg = average power in dBm.
Pin = input power in dBm.
IP3 = third-order intercept point in dBm.
Final ACPR result is displayed in dBc.
Step-by-Step Example
Example: Peak Power = 16 dBm, Average Power = 10 dBm, Input Power = -4 dBm, IP3 = 35 dBm.
Step 1: Crestfactor = Pmax / Pavg = 16 / 10 = 1.6.
Step 2: ACPR = -20.75 + (1.6 × 1.6) + (2 × (-4 - 35)).
Step 3: ACPR = -20.75 + 2.56 - 78 = -96.19 dBc.
Step 4: More negative ACPR means lower adjacent channel leakage in this model.
About This Calculator
Calculate adjacent channel power ratio for RF amplifier linearity checks.
The CalcBoy ACPR Calculator estimates Adjacent Channel Power Ratio in dBc using peak power, average power, input power and third-order intercept point.
Adjacent Channel Power Ratio, often written as ACPR, is used in RF and wireless engineering to estimate how much unwanted distortion energy leaks into nearby channels. In practical transmitter systems, poor amplifier linearity creates spectral regrowth around the wanted channel. That leakage can disturb adjacent channels and may cause a transmitter to fail compliance or mask requirements.
This calculator is useful for RF power amplifier analysis, wireless transmitter design, LTE and 5G linearity review, modulated signal testing, spectrum analyzer interpretation and early distortion estimation. The preserved calculation uses crest factor and IP3-based distortion behavior to produce an ACPR value in dBc.
Use the result as a design estimate. Real ACPR measurement depends on modulation type, bandwidth, measurement filter, spectrum analyzer settings, amplifier bias, thermal state, digital predistortion, output matching and actual nonlinear device behavior. For final RF validation, always compare calculator estimates with real adjacent channel power measurement.
Best UseRF amplifier ACPR and linearity estimation.
Supported InputsPeak power, average power, input power and IP3 in dBm.
Helpful ForRF transmitters, LTE, 5G, PA testing and spectral regrowth review.
Design ReminderActual ACPR must be verified with spectrum analyzer measurement.
Tip: If ACPR is not good enough, designers usually reduce drive level, improve PA linearity, adjust bias, improve matching or use digital predistortion.
Frequently Asked Questions
What is ACPR?
ACPR means Adjacent Channel Power Ratio. It compares unwanted power in an adjacent channel with the wanted main channel power.
What unit is ACPR shown in?
ACPR is commonly shown in dBc, meaning decibels relative to the carrier or main channel.
Why is ACPR important?
It helps evaluate RF transmitter linearity and adjacent channel interference caused by spectral regrowth.
What is IP3 in this calculator?
IP3 is the third-order intercept point, an RF linearity metric used to estimate nonlinear distortion behavior.
Does this replace spectrum analyzer measurement?
No. It provides an estimate. Real ACPR should be measured with correct bandwidth, channel spacing and analyzer settings.
How can ACPR be improved?
ACPR can improve with better amplifier linearity, lower drive level, optimized bias, cleaner matching and digital predistortion.