Does an analog-to-digital converter cost you a lot if you need many bits of accuracy and dynamic range? Absolute accuracy better than 0.1% is likely to be expensive. But a capability for wide dynamic range can be quite inexpensive. Voltage-to-frequency (V-to-F) converters are becoming popular as a low-cost form of A-to-D conversion because they can handle a wide dynamic range of signals with good accuracy.

Source: http://www.national.com/an/AN/AN-240.pdf