Information encoder for encoding an information signal, the information encoder comprising: an analyzer for analyzing the information signal in order to obtain linear prediction coefficients of a predictive polynomial A(z); a converter for converting the linear prediction coefficients of the predictive polynomial A(z) to frequency values f 1...f n of a spectral frequency representation of the predictive polynomial A(z), wherein the converter is configured to determine the frequency values f 1...f n by analyzing a pair of polynomials P(z) and Q(z) being defined as P z = A z + z − m − l A z − 1 and Q z = A z − z − m − l A z − 1, wherein m is an order of the predictive polynomial A(z) and l is greater or equal to zero, wherein the converter is configured to obtain the frequency values (f 1...f n) by establishing a strictly real spectrum derived from P(z) and a strictly imaginary spectrum from Q(z) and by identifying zeros of the strictly real spectrum derived from P(z) and the strictly imaginary spectrum derived from Q(z); a quantizer for obtaining quantized frequency (f q1...f qn) values from the frequency values (f 1...f n); and a bitstream producer for producing a bitstream comprising the quantized frequency values (f q1...f qn) characterized in that the converter comprises a zero-padding device for adding one or more coefficients having a value "0" to the polynomials P(z) and Q(z) so as to produce a pair of elongated polynomials P e (z) and Q e (z); and in that the converter comprises a limiting device for limiting the numerical range of the spectra (RES, IES) of the elongated polynomials P e (z) and Q e (z) or one or more polynomials derived from the elongated polynomials P e (z) and Q e (z) by multiplying the elongated polynomials P e (z) and Q e (z) with a filter polynomial B(z), wherein the filter polynomial B(z) is symmetric and does not have any roots on a unit circle. an analyzer for analyzing the information signal in order to obtain linear prediction coefficients of a predictive polynomial A(z); a converter for converting the linear prediction coefficients of the predictive polynomial A(z) to frequency values f 1...f n of a spectral frequency representation of the predictive polynomial A(z), wherein the converter is configured to determine the frequency values f 1...f n by analyzing a pair of polynomials P(z) and Q(z) being defined as P z = A z + z − m − l A z − 1 and Q z = A z − z − m − l A z − 1, wherein m is an order of the predictive polynomial A(z) and l is greater or equal to zero, wherein the converter is configured to obtain the frequency values (f 1...f n) by establishing a strictly real spectrum derived from P(z) and a strictly imaginary spectrum from Q(z) and by identifying zeros of the strictly real spectrum derived from P(z) and the strictly imaginary spectrum derived from Q(z); a quantizer for obtaining quantized frequency (f q1...f qn) values from the frequency values (f 1...f n); and a bitstream producer for producing a bitstream comprising the quantized frequency values (f q1...f qn) characterized in that the converter comprises a zero-padding device for adding one or more coefficients having a value "0" to the polynomials P(z) and Q(z) so as to produce a pair of elongated polynomials P e (z) and Q e (z); and in that the converter comprises a limiting device for limiting the numerical range of the spectra (RES, IES) of the elongated polynomials P e (z) and Q e (z) or one or more polynomials derived from the elongated polynomials P e (z) and Q e (z) by multiplying the elongated polynomials P e (z) and Q e (z) with a filter polynomial B(z), wherein the filter polynomial B(z) is symmetric and does not have any roots on a unit circle.