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A frequency divider, also called a clock divider or scaler or prescaler, is a circuit that takes an input signal of a frequency, , and generates an output signal of a frequency: f o u t = f i n N {\displaystyle f_{out}={\frac {f_{in}}{N}}}
The counter acts as a frequency divider, counting pulses from a high frequency master clock (typically several MHz) and toggling the state of its output when the count reaches some predetermined value. The frequency of the counter's output can thus be defined by the number of pulses counted, and this generates a square wave at the required ...
When CONTROL is not driven, this divider creates an upper reference voltage of 2 ⁄ 3 V CC and a lower reference voltage of 1 ⁄ 3 V CC. When CONTROL is driven, the upper reference voltage will instead be V CONTROL and the lower reference voltage will be 1 ⁄ 2 V CONTROL.
The lower, yellow trace is the N counter output whose frequency corresponds to the channel spacing frequency of 30 kHz. The green trace is the output from the dual-modulus prescaler, which happens to correspond to 7.1714 MHz in the case that the prescaler is at 128 and 7.1158 when it is at 129.
A prescaler is an electronic counting circuit used to reduce a high frequency electrical signal to a lower frequency by integer division.The prescaler takes the basic timer clock frequency (which may be the CPU clock frequency or may be some higher or lower frequency) and divides it by some value before feeding it to the timer, according to how the prescaler register(s) are configured.
A pulse-swallowing counter is a component in an all-digital feedback system. The divider produces one output pulse for every N counts (N is usually a power of 2) when not swallowing, and per N+1 pulses when the 'swallow' signal is active. The overall pulse-swallowing system is used as part of a fractional-N frequency divider. [1]
The output frequency of a DDS is determined by the value stored in the frequency control register (FCR) (see Fig.1), which in turn controls the NCO's phase accumulator step size. Because the NCO operates in the discrete-time domain, it changes frequency instantaneously at the clock edge coincident with a change in the value stored in the FCR.
The frequency resolution, defined as the smallest possible incremental change in frequency, is given by [6] F r e s = F c l o c k 2 N {\displaystyle F_{res}={\frac {F_{clock}}{2^{N}}}} (2) Equation (1) shows that the phase accumulator can be thought of as a programmable non-integer frequency divider of divide ratio Δ F / 2 N {\displaystyle ...