On 7/21/2016 10:51 PM, Phil Allison wrote:
JC wrote:



Thanks to you and Phil for the info, proved to be very useful and Adobe
Audition seems to be the way to go.

Couple of problems arose.

I need 3 test signals:

JIS (3KHz) 1% @ 4Hz
CCIR (3KHz) 1% @ 4Hz (Same as JIS? Am I missing something here?)
DIN (3.15KHz) 1% @ 4Hz

These should, according to the limited service info I have, produce a 1%
reading on the meter for each relevant setting (JIS, CCIR,DIN)

JIS was giving me 0.5% so I read up on the Adobe Audition settings and I
guess i needed mod by 60 hz, (+/-30Hz). That gave me 1% display with JIS
but then doubles up on the CCIR/DIN giving 2%

JIS is supposedly an effective mean reading, CCIR/DIN are Peak, but I'm
not making sense of these readings, any ideas?



** You have been misled by the wording of the manual - the test signal itself is not being specified, merely the NAME of the test signal.

The actual test signal comes from a special calibration unit where the varying parameters of the several standards have been taken into account - such that using each gives a 1% reading on the meter when set to the matching range.

Inside the meter, once the raw W&F signal has been derived, it is first "weighted" via a filter that emphasises frequencies around 4Hz and is then rectified and measured via a peak reading or average reading meter. W&F tests often use RMS values too.

The use of a dedicated calibrator or a test CD seem to be the only methods possible for results that reliably comply with the various standards.



.... Phil

Quite possible, but I have looked at the cal methods on several W&F
meters and some are explicit on how to generate the signals for DIN. I
would expect an RMS value for JIS to be around 0.7% of the DIN reading
and not exactly half, but without more info or an example from a tape
machine manual giving both figures for comparison I'm probably stuck. I
can adjust the JIS reading to 0.7% but I need more confidence that it
would be correct to do so.

I'm not really sure how much use this meter will be anyway without a
calibration tape. Using the output signal and recording on a machine of
unknown quality then replaying the tape is just compounding errors.

Thanks for everyone's help.