RF Filter Attenuation Data for Romania: 929 Lines in 101 Notations, and 23 Cells Cut Off at 191 Characters

RF filter attenuation specification data from Walsin Technology (Walsin) will not parse with one rule. We split the Attenuation cell of all 235 filters into 929 lines and found 101 notations. A parser written for the commonest one reads 193 lines. And 23 cells are cut off at exactly 191 characters.

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Venatech Limited, an authorised Walsin distributor in Hong Kong, holds the Walsin RF filter export, 235 rows, and its identical twin. This post is written from the Attenuation column of Walsin_Filter.xlsx, read as raw text. A Romanian RF front-end review that wants to script stopband checks across a shortlist meets this column first. Every part number below is real. We hold no Walsin RF datasheet, so every figure is the export’s own value and a shortlisting aid, not a specification.

How many ways does Walsin write one attenuation window in its filter export?

101, and the commonest covers one line in five. We parsed all 235 filter rows, split each Attenuation cell on its line breaks, which gave 929 lines, and replaced every number with N. Those 929 lines collapse into 101 distinct patterns; 37 of them occur exactly once. The commonest, N dB min. @ N ~ N MHz, accounts for 193 lines in 60 filters, 20.8 percent. Ignoring whitespace alone still leaves 46 patterns.

Pattern (numbers replaced by N)	Lines	Filters	A real part carrying it	Match / mismatch against a parser written for the commonest pattern
N dB min. @ N ~ N MHz	193	60	KFBPF2012100C67B1U	reference
N dB min. @ N~N MHz	51	18	RBBPF1005040A1T	Mismatch — no spaces around the tilde
NdB @ N~N MHz	40	10	RFBPF2520080AB7B1U	Mismatch — no space before dB, and no min.
N@ N~ NMHz	53	8	RBBPF2012050AHT	Mismatch — no dB unit written at all
N dB @ N - N MHz	34	10	RFBPF1608060AET	Mismatch — hyphen as the separator, no min.
N dB min. @ N MHz	56	30	RBBPF1411060A8T	Mismatch — one frequency, not a window
N dB typ.@ N ~ N MHz	8	2	RFLPF16081G8D7T	Mismatch — typical, not minimum
NdB @ NGHz	8	3	RFBPF2012100K0T	Mismatch — gigahertz, and the figure is not attenuation (see below)

Among the 736 lines that state a window, the separator is a tilde on 659, a hyphen on 76 and an en dash on 1. We have not seen this counted anywhere. Walsin writes the same idea, “at least this many decibels of rejection across this span”, in 101 spellings, and a filter written for any one of them reads a minority of the file.

Does an attenuation figure say minimum, typical or nothing?

Three different things, depending on the line. We counted the qualifier on every one of the 929 lines. 595 lines say min, 27 say typ and 17 of those say both. 324 lines, 34.9 percent, say neither, so the reader cannot tell whether 20 dB is a guaranteed floor or a measured value. 76 of the 235 filters carry no qualifier on any line.

Qualifier on the line	Lines	What the reader can conclude	Match / mismatch for a worst-case stopband check
min or min.	595	a stated floor	Match — usable as a worst-case figure
typ or typ. only	10	a typical value	Mismatch — not a guarantee
min and typ together	17	a floor and a typical, for example 30 dB min. (35dB typ.) on RFLPF1005040YM1T76	Match on the floor, read the first number only
neither	324	unstated	Mismatch — treat as unknown until the datasheet is read

The 10 typical-only lines come from 27 minus 17. Because we hold no RF datasheet, we cannot say which of the 324 unqualified lines are floors. That is a question for Walsin, and one reason we send every RF enquiry to them with the exact part number.

Where does the export cut the attenuation text off?

At 191 characters, and it does so without warning. We measured the length of every cell in the 17 RF and antenna export files, 11,834 cells. No cell is longer than 191 characters. 23 of the 235 filter Attenuation cells are exactly 191 long, and all 23 end mid-statement. The next longest filter cell is 190 characters, then 184, then 183, so the ceiling is a hard one.

Part	Last line as the export holds it	Match / mismatch for what Walsin presumably wrote
RFBPF2012040AHT	30 dB mi	Mismatch — the qualifier is cut; 8 lines visible, the last one incomplete
RFBPF2012040ABT	32 dB min. @ 1920 ~ 19	Mismatch — the upper edge is cut, so the window reads 1920 to 19
RFBPF3225200Y0T	41 dB min. @ 2	Mismatch — the whole window is gone bar the digit 2
RFBPF1608060K6T	18.0 d	Mismatch — the unit is cut and no window exists
RFLPF2012100F2T	20 dB min. @ 4905	Mismatch — a lower edge with no upper edge
RFBPF2520070AMT	35	Mismatch — a bare number

Each of the 23 cells holds 7 to 11 visible lines. We cannot count how many windows the cut removed, because the removed text is not in the file, and we say so rather than guess. The same ceiling appears elsewhere. We found 41 cells at exactly 191 across five columns in three files: the filter file, the multiplexer file and the SAW filter file.

What does a cut cell do to a tolerant parser?

It breaks the parse on 11 of the 23 cells and corrupts it silently on 12. We wrote a deliberately forgiving expression: optional dB, optional min or typ, optional @, optional second edge, optional unit. It accepts 910 of the 929 lines, 97.9 percent. But 12 of the 23 cut last lines still satisfy it. Nine return a wrong or incomplete window, such as 2 MHz for RFBPF3225200Y0T; three return a window with its unit cut off.

The remaining 19 rejected lines are not all cuts. Eight are real notation oddities: 40 dB @ DC~1600 MHz on RFBPF2012080A7T, a ~- separator on RFLPF1608060AGT, 40dB@4800MHz/ 7200MHz on RFLPF2012110A1T and two harmonic lines, 30 @ 2 x (f0 ± BW/2) and 25 @ 3 x (f0 ± BW/2), on RFLPF2012110A0T. That single part has no frequency window to parse at all. For how the sibling Frequency column is spelled, see choosing an RF chip filter by band.

Does every figure in the attenuation column describe attenuation?

No. Two filters hold insertion loss in it. RFBPF2012100K0T and RFBPF2012100KST are 2012 band pass filters for 4900-5900 MHz. Their Attenuation cells read 1.7dB @ 4.90GHz and 1.5dB @ 4.90GHz, then 1.5 dB at 5.25 and 5.85 GHz. Those frequencies sit inside the passband, and 1.7 matches the Insertion Loss (dB) value of 1.7 on the first part. A script that reads this column as stopband rejection would report 1.7 dB of rejection in the middle of the band.

These are the only two filters whose Attenuation cell uses GHz for a passband figure. The other GHz lines, on RFLPF2012090K0T and RFLPF2012090K07B1U, state 25 to 30 dB at 9.8 and 11.7 GHz, which is stopband for a low pass filter. We checked each against the part’s own Frequency and Insertion Loss cells, and the distinction is only visible by reading the numbers against each other, which is why a scripted read fails.

What should a Romanian design review do before reading this column?

Normalise first, and treat the last line of any 191-character cell as missing. That is how our free cross-reference tool treats these columns, and it is why we state differences from your original rather than hiding them behind a tick. Three rules, each measured above:

1. Never match the column with one pattern. The commonest reads 193 of 929 lines.
2. Flag every cell that is exactly 191 characters. All 23 end mid-statement, and 12 would still parse as something.
3. Cross-check the figure against the passband. If the frequency is inside Frequency, it is not rejection.

We hold 28 Walsin datasheets, 451 pages, and none covers an RF part. Specifications on this line must be confirmed with Walsin for the exact part number, and your incumbent filter needs the same field-by-field check in the last column of any comparison. For the wider RF range, see the Walsin RF balun, filter, coupler and multiplexer overview and the RF product page.

What is in Hong Kong is on ready stock — 1,125 part numbers as at 23 September 2026, a dated snapshot and not a live feed.

The short version

Walsin’s filter export holds attenuation as 929 lines in 101 notations; the commonest reads 193 lines in 60 filters. 595 lines state min, 27 state typ and 324 state neither. 23 of 235 cells stop at exactly 191 characters, all mid-statement, and 12 of those would still satisfy a tolerant parser. Two filters hold insertion loss in the attenuation column. We will not tell you a filter matches on stopband rejection. We will show you the string the file holds. Confirm against both datasheets and qualify in your own circuit.

Send us the filter you use today and the stopband you need, and we will check the Walsin shelf field by field. And a question back: when your script reported 20 dB of rejection, did it know the line had been cut?

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Frequently asked questions

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