GB1111948A - Improved apparatus and method for counting high frequencies - Google Patents

Abstract

1,111,948. Measuring frequencies. W. K. ROSENBERRY, [trading as ABLE RESEARCH Lab.]. 29 July, 1965 [24 Aug., 1964], No. 32443/65. Heading G4H. Apparatus for determining the frequency f 1 of an input signal comprises means for generating a signal related to the frequency of the input signal and this generated signal f 2 being then applied to gating means which are enabled for f 1 a time interval proportional to - so that a f 2 counter counts the cycles of the frequencies f 1 . In one embodiment 12 = # 1 /N 1 (# 1 ) and both signals are applied to a time converter 16 (Fig. 1) where they are proportionally slowed down before being fed into a ratio counter 17, the # 1 output - of which is fed to a time base 18 # 2 which enables a gate 21 for N 1 x 10<SP>-k</SP> secs. so that the count in counter 22 = # 1 x 10<SP>-k</SP>. In a further embodiment (Fig. 3) the signal # 2 is further divided by a factor N 2 and fed together with a frequency ## from an oscillator to a frequency synthesizer the output from which controls a circuit 37 which slows down the input signal # 1 to give an output #<SP>1</SP> 1 = N 1 x N 2 x ##. This output is applied to a gate 38 enabled for 1 a time - to pass N 1 Î N 2 cycles. This output ## is divided by N 2 and applied to a ratio counter and gating means as in the first embodiment. The ratio counter may measure the ratio repetitively, the previous ratio being held in a memory and a parity check circuit comparing the previous ratio with the present ratio.