public String sample_frequency_string () {
		switch (h_sample_frequency) {
		case THIRTYTWO:
			if (h_version == MPEG1)
				return "32 kHz";
			else if (h_version == MPEG2_LSF)
				return "16 kHz";
			else
				// SZD
				return "8 kHz";
		case FOURTYFOUR_POINT_ONE:
			if (h_version == MPEG1)
				return "44.1 kHz";
			else if (h_version == MPEG2_LSF)
				return "22.05 kHz";
			else
				// SZD
				return "11.025 kHz";
		case FOURTYEIGHT:
			if (h_version == MPEG1)
				return "48 kHz";
			else if (h_version == MPEG2_LSF)
				return "24 kHz";
			else
				// SZD
				return "12 kHz";
		}
		return null;
	}