A digital proportional integral loop filter is provided. A first proportional amplification unit multiplies a phase error value by a first proportional loop gain, and a first integral amplification unit multiplies a phase error accumulation value by a first integral loop gain. A second proportional amplification unit multiplies the phase error value by a second proportional loop gain, and a second integral amplification unit multiplies the phase error accumulation value by a second integral loop gain. A first offset value generation unit generates a first offset value by subtracting the second proportional loop gain from the first proportional loop gain and multiplying a resulting value by a phase error average value, and a second offset value generation unit generates a second offset value by subtracting the second integral loop gain from the first integral loop gain and multiplying a resulting value by a phase error accumulation average value.