The definition of an electronic timepiece is: a timepiece in which the time reference (signal) is obtained solely by electronic means.

Given the above definition, G04G covers purely electronic timepieces, namely, electronic timepieces with no moving parts. G04G also covers purely electronic aspects of timepieces having moving parts.

For the overlaps with G04C, see the corresponding section therein.

G04G may overlap with H04M 1/725 and subgroups as well as with H04B 1/385 for documents showing mobile telephones in the form of watches or used according to their timing aspects.

It should always be borne in mind that every document showing a timepicece which is not purely mechanical could potentially be classified in G04G and/or G04C. There are mainly two reasons for this:

1) Often it happens that the nature (electronic or electromechanical) of the timepiece is not the central point in a document. For example, in some cases, despite the presence of moving parts, the core of the document is focused on purely electronic aspects, therefore this document would be classified rather in G04G than G04C.

2) G04C and G04G follow a structure which is only partly parallel (see also the definition of G04C). For example, whilst G04G 15/00 finds an equivalent group in G04C 23/00, other groups such as G04G 17/00, G04G 19/00 or G04G 21/00 have no equivalent in G04C. For this reason, in the practise, some groups of G04G are still used to classify documents showing timepieces with moving parts and for which G04C does not offer a technically detailed possibility for classification.

Documents describing electronic circuits which are usually combined with an oscillator in order to deliver timing pulses in a timepiece.

Frequency dividers, the further breakdown of the classification being self-explaining.

Compensation arrangements for temperature-induced drifts in clocks. The compensations can be either hardware, namely implementing TCXO or "software", namely measuring temperature and correcting the timing pulses by applying predetermined correcting factors obtained using parabolic or cubic models.

Concerning the above limitation with respect to G04F 5/00, it is noted that G04G 3/00 is generally focused on the electronic circuits which deliver the actual timing pulse generated by an oscillator, whereas G04F 5/00 focuses on the generation of the reference frequency itself.

Documents in which details concerning either the hardware or the methods of setting time in electronic timepieces are described.

The expression "time setting" should be intended as an operation which results in the time information as currently measured and displayed by the timepiece to be updated to a (more reliable) value. Time setting can be "immediate", when the updated information is directly overwritten to the pre-existing one. Time setting can also be achieved after a period of merging between the pre-existing time value and the updated one.

Documents describing synchronizations between electronic timepieces. In other words, it describes synchronization between devices which are conceived to measure and display time as their ultimate goal.

As an exception to the above statement, G04G 7/00 can still contain documents which concern synchronization of clocks within telecom networks or satellite systems provided that they strictly related to time-of-the-day information being synchronized and made available to the user.

Both hardware aspects as well as methods related to the display of time, using electronic timepieces.

The so called "analog electronic time displays". In this group, documents will be found showing time displays wherein one indicator refers to an external time scale (be it explicit or implicit) to indicate time. The typical example is an LCD or LED panel wherein each single display element has the shape of a watch hand, the one (or two) element(s) being lit simulating real, physical hands sweeping on a watch face.

The so called "electronic digital displays". Here, one or more character(s) are built-up, e.g. by combining several LED segments, the character(s) being per se capable of delivering the time information, without reference to an external scale.

Combination of G04G 9/02 and G04G 9/08 is represented by the documents in G04G 9/0082.

G04G 9/0023, although apparently limited by a strong precedence rule, is very important for what concerns illumination and back-light (see the lower breakdown). Searches in G04G 9/0023 are often extended to G02F 1/1335+, and/or G02B 6/0001+.

G04G 9/0064 ha no equivalent in G04C. Therefore, this subgroup contains documents showing timepieces with display of time in more than one time zone independently of the nature of the timepiece.

G04G 9/0082 needs always to be searched in combination with G04C 17/0091.

This group corresponds, in G04C, to G04C 19/00 (please refer also to this definition).

G04G 11/00 also completes G04G 9/00 because it focuses on indicating one or more predetermined time visually. The subclass contains, among other, light-based alarms, e.g. for soft awakening of a sleeper.

This subclass corresponds, in G04C, to G04C 21/00 (please refer also to this definition).

Contrary to G04C 21/00, however, G04G 13/00 does not have a specific entry for the classification of electronic "minute repeater", which will therefore classified always in G04C 21/00.

In line with the usual G04C/G04G practical distinction, this subclass contains mostly software/programming/managing details of alarm clocks, as opposed to the more mechanical/hardware aspects of G04C 21/00.

Timepieces which are operable and/or programmable to execute predetermined operations at one or a plurality of predetermined times by means which are not optical nor acoustic.

Typical example is an electronically programmable thermostat or an electronic controller for window blinds.

This group corresponds, in G04C, to G04C 23/00 (please refer also to this definition).

Depending on the specific applications, some overlaps may be found with roller blinds (E06B 9/40), heating systems (F04D 5/00, F24D 11/00).

Some overlaps could also be found with G04F 1/005. The main difference between the two subgroups is: whilst in G04G 15/00 the programmed action happens at a predetermined - measured and therefore known - time of the day, e.g. at 11h24, the devices of G04F 1/005 merely count down starting from a preset time amount. Therefore, the devices of G04F 1/005 are in principle not capable of telling time.

Hardware details concerning mainly two aspects:

G04G 17/02 and subgroups concerns details on how one or more components of the timepiece are assembled with or within the overall structure of the timepiece. For example, it concerns the mounting of the display, the mounting of a sensor inside or onto the timepiece case, etc.

For mountings that could be applied also to mechanical timepieces please refer to G04B 37/00.

G04G 17/08 and subgroups concerns details of the watch case, with the "special cases" represented by watches distributed over several housings (with wired and/or wireless interaction thereof) as well as desktop clocks.

For mountings that could be applied also to mechanical timepieces please refer to G04B 37/00.

The ECLA titles for this subclass are considered to be self-explaining.

Depending on the specific case, searches in this technical area are often extended to H02J 7/00 and subgroups.

Particular attention is drawn to G04G 19/12. This subclass obviously covers the case of purely electronic displays (e.g. LED based) which are switched off when no time display is presumably needed. Nonetheless, due to a lack of an equivalent subclass in G04C, G04G 19/12 also covers the same technology as applied to electromechanical displays, where hands are stopped, e.g., in low illumination conditions. Often the latter case is searched in combination with G04C 3/14 and subgroups as well as with keywords dedicated to the detection of hands positions. If the documents contain details concerning the particular switch used to turn on-off the display, then also G04C 3/001 and subgroups should be considered.