2 Text Corrections and Clarifications

2.1 An Additional Definition

Decimation Factor

The decimation factor gives the reduction of samples in data sections where the sampling rate is reduced with reference to the original sampling rate (Note: This only applies for bimodal data compression). For example original sampling rate 500 S/s (which is equivalent to a sample interval of 2 ms) is reduced to 125 S/s (which is equivalent to a sample interval of 8 ms). The decimation factor is than 4.

2.2 Text Corrections

Section 1 clause 5.4.5 tag 10.

There was an editorial error. The correct text should read:

---

10	length	Drugs (Three binary and Text characters)
		Each drug entered in the patient demographic area shall be described by the following structure:
		Byte	Contents
		1	Drug code table indicator. If byte 1 is set to 0, then the following table applies
		2	Class code
		3	Specific drug code within the specified class
		4 - ***	Text description of the drug (optional).

---

The remaining text regarding tag 10 resembles with the text in version 1.0.

Section 1 clause 5.4.5 tag 34.

The text currently is:

---

34	length	Date Time Zone
		...
		Byte	Name	Type	Notes
		1-2	Offset	signed integer	...
					...
		3-4	Index	unsigned byte	...

---

The terms "signed integer" and "unsigned byte" must be exchanged respectively with "signed binary" and "unsigned binary", furthermore, close to Date Time Zone there should be the type of this tag.

In conclusion the text should be:

---

34	length	Date Time Zone (Binary bytes and Text characters)
		...
		Byte	Name	Type	Notes
		1-2	Offset	signed binary	...
					...
		3-4	Index	unsigned binary	...

---

Section 3 clause 5.6.

Please note: Leads may be acquired in subgroups simultaneously or all leads simultaneously. However, the SCP structure requires that the leads are stored in sequential order sample-by-sample. Index of first sample is 1, index of last sample is N.

The leads are identified by codes defined in the table of clause 5.6.3.

Section 4 clause 5.7.

This clause describes organization and identification of data based on the assumption that compression as described in Annex C is applied. Since there are at least four different options for data formatting (a) Original raw data without compression, (b) Original raw data with lossless compression with entropy encoding, (c) Original raw data with lossless compression without entropy encoding and (d) Lossy high compression, the reader should study Annex C before continuing to study section 4.

Section 5 clause 5.8.

For better understanding of the definitions and specifications the reader should have studied Annex C.

Please Note: For the tables of note 3 and 4 it should be kept in mind that within tables 3 and 4 the running sample number is "n" instead of "N". "N" denotes the total number of samples for a lead.

Section 6 clause 5.9.

This section deals again with data compression. See text above and Annex C.

Section 7 clause 5.10.

The text of the standard document and Part I of the "How To Implement SCP, Part I" document contains the necessary descriptions and explanations.

Please observe specifically clause 5.10.2.

For handling of SCP measurements in a database it is relevant that it is identified if a measurement has not been computed by an analysis program or a measurement result has not been found (e.g. due to rejection of the measurement program or due to the fact that a measurement was not found because a wave was not present (e.g. P wave during atrial fibrillation)).

This clause has been introduced to avoid errors of data analysis in statistical investigations. If for example "0" is inserted instead of the respective code statistical results may be seriously distorted. The reader may keep in mind the data analysis for clinical studies.

Section 8 clause 5.11.

There are no specific comments at this time.

Section 9 clause 5.12.

There are no specific comments at this time.

Section 10 clause 5.13.

There are no specific comments at this time.

Section 11 clause 5.14.

There are no specific comments at this time.

2.3 Further Suggestions

However there is at present in various standardization organizations (CEN TC251, ISO TC215, the IEEE11073 WG and HL7) extensive activity on standardizing the nomenclature and associated code schemes. Depending on the application of the respective device, the manufacturer should check to which extent the results of these standardization activities should be implemented.