The typical IR spectrometer broadband source emits all IR frequencies of interest simultaneously I am currently studying the textbook Infrared and Raman Spectroscopy, 2nd edition, by Peter Larkin. In a section entitled Infrared Absorption Process, the author says the following:

The typical IR spectrometer broadband source emits all IR frequencies of interest simultaneously where the near-IR region is 14,000 - 4000 cm$^{-1}$, the mid-IR region is 4000 - 400 cm$^{-1}$, and the far-IR region is 400 - 10 cm$^{-1}$.

I know that lasers are approximately, more or less, monochromatic. Obviously, wavelength is not the same thing as frequency, but the idea that a light source could simultaneously emit a broad range of frequencies made me uncomfortable, given the aforementioned fact about monochromaticity. 
In doing research, I found the following explanation (see 10.6.2 Sensing Mechanisms):

Optical sensors are typically interfaced with an optical module, as shown in Figure 10.38. The module supplies the excitation light, which may be from a monochromatic source such as a diode laser or from a broadband source (e.g., quartz-halogen) that is filtered to provide a narrow bandwidth of excitation.

It seems to me that this explanation confuses the concepts of "broadband" and "monochromaticity", or it at least writes in such a way that makes it seem so: 

The module supplies the excitation light, which may be from a monochromatic source such as a diode laser or from a broadband source (e.g., quartz-halogen) ...

I would greatly appreciate it if people would please take the time to explain how a light source can be "broadband" (that is, emit a broad range of frequencies), and clarify what the above explanation is saying
 A: Thermal emission (often idealized as blackbody radiation) is broadband, i.e. emitting multiple frequencies at once. An incandescent lightbulb is like this. The references provided in the question make a proper distinction between monochromatic emission from lasers, and broadband emission from thermal sources.
The quoted sentence that mentions the quartz-halogen source indicates that its broadband emission must be filtered in order to make it behave more like a monochromatic source - without the filter, it doesn't have that property.
A: There are two possible routes to making a broadband light source.


*

*Incoherent sources
The first way is to make a source that emits light at a bunch of different frequencies without any coherence between those different frequency components. The easiest way to do this is via thermal sources (like the quartz-halogen lamps mentioned as examples in your quote) but there are also other mechanisms such as e.g. fluorescence.

*Coherent sources
Or, in other words, pulsed lasers. To be blunt, when you say

I know that lasers are approximately, more or less, monochromatic

you 'know' wrong. Lasers are indeed often described as producing light of only one frequency, but this is a misconception. Lasers come from the amplification of light via stimulated emission, and this amplification can happen for any frequency where the gain medium has available transitions. For solid-state systems, these transitions often occur over broad frequency bands, so those gain media can be used as 'tunable' lasers (where you use the cavity to select the frequency that gets amplified), but you can also set them up so that all of the frequencies are amplified at the same time, fixing their relative phase so that they are coherent with each other, which results in a series of (often very short) laser pulses.
Because of the added layers of technology, pulsed lasers are often more expensive than thermal sources (which can be extremely simple), so if you don't need the coherence (such as e.g. in a spectrometer) then you just use thermal sources when you need broadband light.
