The PHB states that a wizard can copy a known spell onto another spellbook.
Replacing the Book. You can copy a spell from your own spellbook into another book—for example, if you want to make a backup copy of your spellbook. This is just like copying a new spell into your spellbook, but faster and easier, since you understand your own notation and already know how to cast the spell. You need spend only 1 hour and 10 gp for each level of the copied spell.
What about copying an unknown spell without transcribing it ?
IE My wizard PC finds a spellbook containing several interesting spells, but for any reason he cannot take the spellbook away.
Can he copy the spells onto parchment, that can be a valid spellbook1, then save it for later transcription ?
Would an Intelligence (Arcana) check be required to correctly grasp the other wizard notation system and produce a usable copy ?
The surefire solution would be to ask the other wizard to produce the copy himself, but that supposes a friendly, living, available, …, other wizard.
1 PHB about a spellbook appearance :
The Book’s Appearance. Your Spellbook is a unique compilation of Spells, with its own decorative flourishes and margin notes. It might be a plain, functional leather volume that you received as a gift from your Master, a finely bound gilt-edged tome you found in an ancient Library, or even a loose collection of notes scrounged together after you lost your previous Spellbook in a mishap.
Best Answer
Your DM needs to decide
The rules on page 114 of the PHB only cover transcribing the spells into your own notation into your spell book (also called copying), and copying spells that are already transcribed into your own notation into another book.
However, it is established that normal spellbooks are not magical. That means, it should be possible to create an exact one-to-one copy of an existing spellbook.
How this could be achieved would be up to your DM to adjucate.
As you do not know which little splurch and dot is or is not important to the functioning of the spell before transcribing it into your own notation, you would not be able to leave anything out and would need to create an exact replica of the original symbols. This very similar to a forgery, if you so want. There are rules in the game to forge documents, and they require tool proficiency in the forgery kit. You DM could rule that you need to spend downtime to forge the copy.
Alternatively, when you copy your own spells you do need only inks worth 10 gp and one hour, as you cite above. Your DM could rule that copying a spell without understanding could be done at the same cost, maybe with an Intelligence (Arcana) skill check or a Dexterity ability check, as you save yourself all the time and cost of experimenting to understand the spell. Or they could rule that it takes longer and costs more. It's up to them to decide.