Thursday, May 8, 2014

Board finds that "band of frequencies" does not require range and reads on single clock frequency

Takeaway: The Applicant appealed claims to a memory controller using two frequency bands to communicate with a memory device. The Examiner rejected as anticipated by a reference that taught the use of two clock frequencies (X and X/2). The Applicant appealed and argued that "band of frequencies" implies a range, and thus does not read on a single frequency. The Board affirmed the rejection because the Applicant's specification discussed an embodiment using a "zero band of frequencies", which the Board interpreted as a single frequency.


Ex parte Alon
Appeal 2010008694; Appl. No. 11/021,514; Tech. Center 2600
Decided: Feb. 19, 2013

The application was directed to a memory controller with a simultaneous bi-directional link to the memory. A representative claim on appeal read:

     1. A memory system, comprising:
     a controller;
     a memory device; and
     a set of signal lines, coupled to the controller and the memory device,
     wherein, on each of the signal lines, the controller is to communicate to the memory device using a first band of frequencies while the memory device is communicating to the controller using a second band of frequencies, and
     wherein the controller is configured to dynamically adjust the first band of frequencies based on a predetermined data rate from the controller to the memory device
and to dynamically adjust the second band of frequencies based on a predetermined data rate from the memory device to the controller.

The Examiner asserted that Koroodi's teaching of a clock rate of X Mhz and a clock rate of X/2 MHz read on the "first band of frequencies" and "second band of frequencies". The Applicant appealed and argued that reading "band of frequencies" on a single clock frequency was an unreasonably broad interpretation of "band".

The Applicant made several points related to Broadest Reasonable Interpretation. According to the Applicant, "the clock rate of a controller is a distinct technical concept from frequency bands for communication, such as for communication from a controller to a memory device or a memory device to a controller", and the Examiner violated the BRI requirement by equating these "distinct concepts".

Moreover, the Applicant argued, "band of frequencies" means a range of frequencies, and does not read on a single frequency as asserted by the Examiner. As support for this argument, the Applicant referred to Fig. 3's depiction of "first band of frequencies 364" as encompassing a range of frequencies 368. According the Applicant, this would teach a person of ordinary skill in the art (POSITA) that "band of frequencies" included multiple frequencies. The Applicant then referenced other uses of the term "band" in the art, asserting that "a band-pass filter passes a specified range of frequencies while filtering out frequencies outside the specified range." According to the Applicant, this shows that a POSITA would understand "band" as "range", even without consulting the specification.

Neither party disputed that Kuroodi taught a single clock frequency rather than a range. Thus, the Applicant concluded that under a reasonable interpretation, Kuroodi did not teach the claimed "range of frequencies."

In the Answer, the Examiner responded to the Appeal Brief arguments by stating that "the Examiner is not limited to Applicant's definition, which is not specifically set forth in the claims. In re Tanaka et al. 193 USPQ 139, (CCPA) 1977.

The Board found the Examiner's interpretation to be reasonable, and affirmed the anticipation rejection. After explicitly adopting the Examiner's finding and reasoning, and concurring with the Examiner's conclusions, the Board offered this additional explanation.

The Board first indicated that the Examiner's requirement for a definition to be incorporated into the claims was improper. The Board then noted that the claim term should be afforded its plain meaning since the Applicant's specification did not provide a definition for the term.

The Board was not persuaded by the Applicant's first BRI argument – that clock rate and communication frequency – are different, and instead concluded that a clock rate may be expressed as a frequency.

As for the second BRI argument  – that "band" did not encompass a single frequency – the Board found that the specification taught to the contrary. More specifically,  para. 044 of the Applicant's specification "provides an example in which there is a 'zero band of frequencies' ". ( "The memory system 200 may have a mode of operation in which the control logic 210 allocates a substantially zero band of frequencies to the first band of frequencies 368 (FIG. 3) and a maximum band of frequencies to the second band of frequencies 370 (FIG. 3) ..."

The Applicant made other arguments as well, but the Board was not persuaded by these either, and affirmed the anticipation rejection.

My two cents: The Board interpreted "zero band" as a single frequency. But it seems to me that the discussion of "zero band" in Applicant's spec was really saying that one embodiment allocated NO frequencies to one direction, and all of the frequencies to the other. In fact, I'd say this is how a POSITA would understand the spec as written.

Perhaps if the drafter had used this more straightforward phrasing, instead of "zero band", the Board would have ruled differently. This embodiment was captured in an original dependent claim. Perhaps the drafter was taught to avoid claiming a negative ("allocate no frequencies")? Could the Applicant have covered this embodiment by simply claiming "allocate all of the frequency band" to the other direction?


  1. Thanks Karen: my reading of the Board's interpretation you cited is that if the range of what the applicant meant by "band" includes an empty band, then that range must also include a band of a single frequency.

  2. Hi Karen: I do not agree with you regarding the "zero band". I think the examiner got it right and that the zero band means a "single" frequency. In order for the controller to communicate to the memory device there must be some frequency allocated to the channel. From information theory we know that you cannot communicate with a true single frequency (it would be a sine wave that continues for all time, unchanged in amplitude and phase) so I believe that the inventor intended to claim a very narrow frequency band - one that is adequately wide to carry the minimal information that is required for that mode of operation. That is why the specification says "substantially zero band".

    A "substantially zero band" channel means, to a POSITA, the same thing as a "single" frequency communication channel, since, as mentioned above, you can't really have a single frequency communications channel.

  3. I don't understand why this appeal was filed at first place. The applicant could have just put into the claim that a band includes a range of frequencies. He had ample support, and his appeal brief limited the interpretation of the claim in future litigation whether he amends the claim or not. So what's the point of appeal?