Microphone NF meaning ?

[DMcMahon]

I am sure it must be simple but I cannot think what "NF" means on the internal condensor microphone output as shown on this attached schematic section.

The schematic section shown is for the Grundig C 430 Stereo cassette recorder, the same applies for the Grundig C 403/C 411 Mono recorders.

David

[ms660]

Low frequency ?

Lawrence.

[eddie_ce]

As has been pointed out Nieder Frequenz. In other words = (low) audio frequency.

[DMcMahon]

Thank you Lawrence and Eddie.

I do not think I have seen the NF designation before on microphone documentation.

Typical microphones as used on audio equipement would cover a certain audio frequency range so in that case all could be called low frequency, so still not clear to me why this particular schematic specifies NF, unless it is implying that the frequency range using the internal microphone is low/lower than a good external microphone (internal microphones of course are often not great).

The frequecy range spec for the whole machine is 60Hz - 10kHz (no dB tolerance given).

David

[eddie_ce]

NF is a generic descriptor to differentiate between HF (high frequency) and is very commonly used for anything audio here in D.

[DMcMahon]

Thank you Eddie, certainly not a descriptor I am familiar with, may have forgotten of course due to age

See you are near Hannover, I was born there in the British Military Hospital (since converted into flats/apartments).

David

[ms660]

NF was new to me as well, it being German but LF isn't, it's often used in reference to AF.

I was in Hanover once, Expo 2000, I was on the construction crew for Daimler Chrysler's Lab 01 project, the TV displays were plasma screen, stayed at the Pannonia (now Wyndham) Nice hotel.

Lawrence.

[DMcMahon]

Obvioulsy knew that LF = Low Frequency and that audio frequncies (AF) would be in the low frequency spectrum band but would not associate LF to mean specifically AF.

I see that in terms of radio frequncies/wavelengths, the LF band is 30Hz to 300kHz, so goes somewhat above my audible hearing range

David

[ms660]

Eg: LF choke, my thoughts would immediately be HT choke or AF choke.

Lawrence.

[duncanlowe]

Yes, I agree, you have your answer. NF is equivalent to AF in English. I used to see it often in schematics from Germany.

[lesmw0sec]

As an aside, German/English/German usually translates very well, but I recall being amused by a definition in a Siemens manual for a particular IC. They were rated as standard, fast, and damned fast! Often wondered if this was a translation error or an office joke. It certainly entertained us...

[Herald1360]

In the circuit shown, the microphone has power connections as well as the audio out connection. Whilst the symbol makes it obvious (to me anyway) where the audio comes out, adding NF nails it home (if you know technical German at any rate).

[DMcMahon]

Agreed, I will have to keep an eye open for NF on other schematics, pretty sure I have not seen it before (or at least noticed it).

David

[emeritus]

"Damned fast" was a designation used by a US firm for one of their products in the early 1970's, I think for a comparator or op amp.